Abstract: A technique for maintaining maximum unipolar current density while improving I2t tolerance is provided. In a semiconductor device, a first impurity layer and a Schottky interface are formed to sandwich a well layer therebetween. A first impurity layer is formed from an outermost layer of the well layer located closer to the Schottky interface than a source layer to below the source layer. The lower face of the first impurity layer is located below the Schottky interface.

Abstract: A semiconductor device includes a semiconductor base body, and a first main electrode and a second main electrode provided on the semiconductor base body. The semiconductor base body includes a drift region of a first conductivity type through which a main current flows, a column region of a second conductivity type arranged adjacent to the drift region in parallel to a current passage of the main current, a second electrode-connection region of the first conductivity type electrically connected to the second main electrode, and a low-density electric-field relaxation region of the first conductivity type having a lower impurity concentration than the drift region and arranged between the second electrode-connection region and the column region.

Abstract: A lateral double-diffused metal-oxide-semiconductor (LDMOS) transistor including a breakdown voltage clamp includes a drain n+ region, a source n+ region, a gate, and a p-type reduced surface field (PRSF) layer including one or more bridge portions. Each of the one or more bridge portions extends below the drain n+ region in a thickness direction. Another LDMOS transistor includes a drain n+ region, a source n+ region, a gate, an n-type reduced surface field (NRSF) layer disposed between the source n+ region and the drain n+ region in a lateral direction, a PRSF layer disposed below the NRSF layer in a thickness direction orthogonal to the lateral direction, and a p-type buried layer (PBL) disposed below the PRSF layer in the thickness direction. The drain n+ region is disposed over the PBL in the thickness direction.

Abstract: A semiconductor device includes a semiconductor base body, and a first main electrode and a second main electrode provided on the semiconductor base body. The semiconductor base body includes a drift region of a first conductivity type through which a main current flows, a column region of a second conductivity type arranged adjacent to the drift region in parallel to a current passage of the main current, a second electrode-connection region of the first conductivity type electrically connected to the second main electrode, and a low-density electric-field relaxation region of the first conductivity type having a lower impurity concentration than the drift region and arranged between the second electrode-connection region and the column region.

Abstract: Integrated circuit (IC) structures including buried insulator layer and methods for forming are provided. In a non-limiting example, a IC structure includes: a substrate; a first fin over the substrate; a source region and a drain region in the first fin; a first gate structure and a second gate structure over the first fin, the first and the second gate structures positioned between the source region and the drain region; and a buried insulator layer including a portion disposed under the first fin.

Abstract: A semiconductor device includes a semiconductor substrate. A drift region is disposed in the semiconductor substrate. The drift region has a first conductivity type. A body region is disposed in the semiconductor substrate, adjacent to the drift region. The body region has a second conductivity type. A drain region is disposed opposite to the body region in the drift region. A drain isolation insulating film is disposed in a portion adjacent to the drain region of the drift region. A gate insulating film is disposed on the semiconductor substrate and is extended over a portion of the body region and a portion of the drift region. A gate electrode is disposed on the gate insulating film and the gate electrode has at least one closed-type opening.

Abstract: A structure includes a first source/drain region and a second source/drain region in a semiconductor body; and a trench isolation between the first and second source/drain regions in the semiconductor body. A first doping region is about the first source/drain region, a second doping region about the second source/drain region, and the trench isolation is within the second doping region. A third doping region is adjacent to the first doping region and extend partially into the second doping region to create a charge trap section. A gate conductor of a gate structure is over the trench isolation and the first, second, and third doping regions. The charge trap section creates a charge controlled e-fuse operable by applying a stress voltage to the gate conductor.

Abstract: The present disclosure provides a high voltage semiconductor device includes a substrate, a first well region, a second well region, a source, a drain, a first electrode structure and a second electrode structure. The first well region and the second well region are disposed in the substrate, and which includes a first conductive type and a second conductive type which are complementary with each other. The source and the drain are respectively disposed within the first well region and the second well region. The first electrode structure and the second electrode structure are both disposed on the substrate, and the distance between the top surface of an electrode of the first electrode structure and the top surface of the substrate includes a first height and a second height which are different from each other.

Abstract: Various embodiments of the present disclosure are directed towards a method for forming an integrated chip. The method includes forming a source region and a drain region within a substrate. A drift region is formed within the substrate such that the drift region is disposed laterally between the source region and the drain region. A first gate structure is formed over the drift region. An inter-level dielectric (ILD) layer is formed over the first gate structure. The ILD layers is patterned to define a field plate opening. A first field plate layer, a second field plate layer, and a third field plate layer are formed within the field plate opening.

Abstract: A manufacturing method of an LDMOS device comprises: obtaining a wafer formed with a doped region having a first conductivity type, wherein a top buried layer is formed inside the doped region having the first conductivity type, and a field oxide insulation layer structure is formed on the top buried layer; disposing a trench on the doped region having the first conductivity type, wherein the trench extends to the top buried layer and the field oxide insulation layer structure such that a portion of the top buried layer is removed; injecting an ion of a second conductivity type to form a well region below the trench; and forming a doped source region in the well region. The first conductivity type and the second conductivity type are opposite conductivity types.

Abstract: A lateral double diffused metal oxide semiconductor (LDMOS) transistor and a semiconductor can reduce the size of the entire power block and can decrease costs by preventing formation of an edge termination region between adjacent device tips or ends along a width direction when the corresponding LDMOS transistor cell has a limited width and the LDMOS transistor is a multi-finger LDMOS transistor.

Abstract: A semiconductor device includes a semiconductor substrate having a first conductivity type. First and second wells are located within the substrate, the first well being formed with a dopant of the first conductivity type, e.g. n-type, and the second well formed with a dopant of a second different conductivity type, e.g. p-type. A doped gap region is located between the first and second wells. The doped gap region is formed with a dopant of the second conductivity type, e.g. p-type, at a lower dopant concentration than the dopant concentration in the second well.

Abstract: A technique is provided for effectively suppressing a forward voltage shift due to occurrence of a stacking fault. A semiconductor device relating to the present technique includes a first well region of a second conductivity type, a second well region of the second conductivity type which is so provided as to sandwich the whole of a plurality of first well regions in a plan view and has an area larger than that of each of the first well regions, a third well region of the second conductivity type which is so provided as to sandwich the second well region in a plan view and has an area larger than that of the second well region, and a dividing region of a first conductivity type provided between the second well region and the third well region, having an upper surface which is in contact with an insulator.

Abstract: Methods of fabricating a field-effect transistor, where the methods include providing a substrate, forming a first well of a first doping polarity type in the substrate, and forming a gate on a portion of the first well, the gate comprising an oxide layer and an at least partially conductive layer on the oxide layer. A second well of a second doping polarity type is formed by implanting ions in the first well, the second well extending under a portion of the gate. A first one of a source and drain of the first doping polarity type in or on the second well is formed, thereby defining a channel of the transistor under the gate. A second one of the source and drain of the first doping polarity type in or on the first well is formed. The second well may be formed by means of a two-step implant.

Abstract: A semiconductor structure and a method for forming a semiconductor structure are disclosed. A forming method may include: providing a base, including a first region used to form a well region and a second region used to form a drift region, where the first region is adjacent to the second region; and patterning the base, to form a substrate and fins protruding out of the substrate, where the fins include first fins located at a junction of the first region and the second region and second fins located on the second region, where the quantity of the second fins is greater than the quantity of the first fins. In some implementations of the present disclosure, the quantity of the second fins is increased to correspondingly increase the length of a flow path in which a current flows from a drain region to a source region, thereby reducing a voltage drop in the current flow path, and further improving a breakdown voltage of an LDMOS, to improve the device performance of the LDMOS.

Abstract: A gate driver integrated circuit is provided. The gate driver integrated circuit includes a first well region disposed at one side of a first gate structure near an isolation region, and a second gate structure between the first well region and the isolation region. The second gate structure is used to suppress a leakage current in a parasitic PN junction formed by a drift region between the first well region and the isolation region. A performance of the gate driver integrated circuit is improved.

Abstract: A semiconductor body includes first and second opposing surfaces, an edge extending in a vertical direction substantially perpendicular to the first surface, an active area, a peripheral area arranged in a horizontal direction substantially parallel to the first surface between the active area and edge, and a pn-junction extending from the active area into the peripheral area. In the peripheral area the semiconductor device further includes a first conductive region arranged next to the first surface, a second conductive region arranged next to the first surface, and arranged in the horizontal direction between the first conductive region and edge, and a passivation structure including a first portion at least partly covering the first conductive region, a second portion at least partly covering the second conductive region. The first portion has a different layer composition than the second portion and/or a thickness which differs from the thickness of the second portion.

Abstract: Disclosed examples include LDMOS transistors and integrated circuits with a gate, a body region implanted in the substrate to provide a channel region under a portion of the gate, a source adjacent the channel region, a drain laterally spaced from a first side of the gate, a drift region including a first highly doped drift region portion, a low doped gap drift region above the first highly doped drift region portion, and a second highly doped region portion above the gap drift region, and an isolation structure extending through the second highly doped region portion into the gap drift region portion, with a first end proximate the drain region and a second end under the gate dielectric layer, where the body region includes a tapered side laterally spaced from the second end of the isolation structure to define a trapezoidal JFET region.

Abstract: A semiconductor device (1) includes a drain region (14) of a first conductivity type which includes a high-concentration drain region (14a), a first drain drift-region (14b), and a second drain drift-region (14c) of the first conductivity type, a source region (15) of the first conductivity type, a body region (16) of a second conductivity type, a gate insulating film (12), a gate electrode (13), and an STI insulating film (11) formed on the drain region (14). The second drain drift-region (14c) is formed from a first position (11f) of the STI insulating film (11) which is away from a first corner portion (11a) by a distance (x1) in a direction of a second corner portion (11b).

Abstract: A silicon carbide semiconductor device has an n-type drift layer provided on a front surface of an n+-type silicon carbide substrate. In a surface layer of the n-type drift layer, a first p+-type region is provided. On a front surface side of the n+-type silicon carbide substrate, a trench is formed. The first p+-type region includes a deep first p+-type region and a shallow first p+-type region, the deep first p+-type region being at a position farther toward a drain electrode than a bottom of the trench is and the shallow first p+-type region being at a position closer to a source region than the bottom of the trench is. An impurity concentration of the shallow first p+-type region is lower than an impurity concentration of the deep first p+-type region.

Abstract: An ESD protection device includes a substrate structure having a substrate, first and second fins, and first and second doped regions having different conductivity types. The first doped region includes a first portion of the substrate and a first region of the first fin, the second doped region includes a second portion of the substrate, a second region of the first fin adjacent to the first region and the second fin. The ESD device also includes a first gate structure on a surface portion of the first region and on an entire surface of the second region of the first fin and including, from bottom to top, an interface layer on the surface portion of the first region and the surface portion of the second region of the first fin, a spacer, a high-k dielectric layer, a first work-function adjusting layer, a second work-function adjusting layer, and a gate.

Abstract: In an embodiment, a semiconductor device includes a semiconductor substrate having a front surface, a LDMOS transistor in the front surface, and a metallization structure arranged on the front surface. The metallization structure includes at least one cavity arranged in at least one dielectric layer. Related methods of manufacture are also described.

Abstract: A semiconductor device includes a semiconductor substrate having a first conductivity type. First and second wells are located within the substrate, the first well being formed with a dopant of the first conductivity type, e.g. n-type, and the second well formed with a dopant of a second different conductivity type, e.g. p-type. A doped gap region is located between the first and second wells. The doped gap region is formed with a dopant of the second conductivity type, e.g. p-type, at a lower dopant concertation than the dopant concentration in the second well.

Abstract: A high voltage MOS device includes: a first drift region with a first conductive type, a body region with a second conductive type, plural second drift regions with the second conductive type, a gate, a source region with the first conductive type, a drain with the first conductive type, and a body contact region with the second conductive type. The plural second drift regions contact the body region along the lateral direction, and are located separately in the width direction. Any neighboring two second drift regions do not contact each other. Each of the second drift regions is separated from the drain by the first drift region.

Abstract: A method of manufacturing a semiconductor device is provided. The semiconductor device includes a semiconductor substrate, first and second fins on the semiconductor substrate and separated by a trench. The first fin includes a first portion having a first conductivity type and a second portion having a second conductivity type different from the first conductivity type, the first and second portions are adjacent to each other, and the second portion connected to the second fin through the semiconductor substrate. The semiconductor device also includes a gate structure on the first and second portions and including a gate insulator layer on the first and second portions, a gate on a portion of the gate insulator layer on the first portion, and a dummy gate on the second portion and including an insulating layer or an undoped semiconductor layer and adjacent to the gate.

Abstract: A Lateral Diffusion Metal Oxide Semiconductor (LDMOS) device and its manufacturing method are presented. The LDMOS device comprises a first region that has a first conductivity type; a drift region that has a second conductivity type in the first region, wherein the second conductivity type is opposite to the first conductivity type; and a plurality of second regions that have the first conductivity type in the drift region, wherein the second regions are separated from each other and extend to the first region along a depth direction of the drift region. This LDMOS device has an higher Breakdown Voltage and thus better performance than conventional LDMOS devices.

Abstract: A dual-gate metal-oxide-semiconductor field-effect transistor (MOSFET) may include a MOSFET having a channel region, a drain, and a source, a first gate formed proximate to the channel region, a drain extension region formed proximate to the drain, and a second gate formed proximate to the drain extension region.

Abstract: A structure for improved noise signal isolation in semiconductor devices. In one embodiment, the structure includes a second-conductivity type substrate, a 1st first-conductivity type well, a 1st first-conductivity type layer, a second-conductivity type layer positioned between the 1st first-conductivity type well and the 1st first-conductivity type layer. The structure also includes a 2nd first-conductivity type well, and a 2nd first-conductivity type layer positioned between the 2nd first-conductivity type well and the 1st first-conductivity type layer. The 1st first-conductivity type layer and the second-conductivity type layer are positioned between the P type substrate and the 1st first-conductivity type well, and the 1st first-conductivity type well is laterally separated from the 2nd first-conductivity type well.

Abstract: A transistor includes a trench formed in a semiconductor substrate with the trench having a first sidewall and a second sidewall. A vertical field plate is formed in the trench and the vertical field plate is located between the first sidewall and the second sidewall. A gate electrode is formed in the trench with a first edge of the gate electrode proximate to the first sidewall and a second edge of the gate electrode proximate to the vertical field plate. A first dielectric material is formed in the trench between the first sidewall and the vertical field plate. A second dielectric material is formed in the trench between the vertical field plate and the second sidewall with the second dielectric material having a dielectric constant lower than that of the first dielectric material.

Abstract: The disclosure relates to a negative charge pump circuit including a first capacitor; a first selector switch; a second selector switch; and a control circuit designed to, in a first phase of operation, alternately control the first and second selector switches in a first configuration in which the first and second electrodes of the first capacitor are respectively linked to the first and second nodes and in a second configuration in which the first and second electrodes of the first capacitor are respectively linked to the second and third nodes. In a second phase of operation, the control circuit forces the first selector switch to link the first electrode of the first capacitor to the second node and control the second selector switch so as to alternately link the second electrode of the first capacitor to the second and to the third node.

Abstract: A semiconductor structure includes a substrate, at least one active semiconductor fin, at least one insulating structure, a gate electrode, and a gate dielectric. The active semiconductor fin is disposed on the substrate. The insulating structure is disposed on the substrate and adjacent to the active semiconductor fin. A top surface of the insulating structure is non-concave and is lower than a top surface of the active semiconductor fin. The gate electrode is disposed over the active semiconductor fin. The gate dielectric is disposed between the gate electrode and the active semiconductor fin.

Abstract: An n-type region and a p-type region of a first parallel pn layer are arranged parallel to a base front surface, in a striped planar layout extending from an active region over an edge termination region. In the n-type region, a gate trench extending linearly along a first direction is provided. In an intermediate region, in a surface region on the base front surface side of the first parallel pn layer, a second parallel pn layer is provided. The second parallel pn layer is arranged having a repetition cycle shifted along a second direction ½ a cell with respect to a repetition cycle of the n-type region and the p-type region of the first parallel pn layer. A gate trench termination portion terminates in the intermediate region between the active region and the edge termination region, and is covered by the p-type region of the second parallel pn layer.

Abstract: A method for forming a high voltage device is disclosed. The method comprises providing a substrate defined with a high voltage device region. A device well is formed to encompass the high voltage device region. A drift region is formed within the device well. A body well is formed within the device well adjacent to the drift region. A variable thickness gate dielectric is formed on the substrate. Forming the variable thickness gate dielectric comprises patterned a sacrificial polysilicon layer and oxidizing the patterned sacrificial polysilicon layer to define a thick gate oxide having sloped sidewalls. A gate electrode is formed on the variable thickness gate dielectric, wherein the gate electrode partially overlaps the thick gate oxide. A first and a second source/drain (S/D) region is formed adjacent to first and second sides of the variable thickness gate dielectric.

Abstract: A Lateral Diffusion Metal Oxide Semiconductor (LDMOS) device and its manufacturing method are presented. The LDMOS device comprises a first region that has a first conductivity type; a drift region that has a second conductivity type in the first region, wherein the second conductivity type is opposite to the first conductivity type; and a plurality of second regions that have the first conductivity type in the drift region, wherein the second regions are separated from each other and extend to the first region along a depth direction of the drift region. This LDMOS device has an higher Breakdown Voltage and thus better performance than conventional LDMOS devices.

Abstract: A semiconductor device includes: a gate structure extending along a first direction on a substrate, in which the gate structure includes a first edge and a second edge extending along the first direction; a first doped region adjacent to one side of the gate structure, in which the first doped region includes a third edge and a fourth edge extending along the first direction; a second doped region adjacent to another side of the gate structure, in which the second doped region comprises a fifth edge and a sixth edge extending along the first direction; a first fin-shaped structure extending from the second edge of the gate structure toward the third edge of the first doped region; and a second fin-shaped structure extending from the first edge of the gate structure toward the sixth edge of the second doped region.

Abstract: A high-side device includes: a substrate, an epitaxial layer, a high voltage well, a body region, a gate, a source, a drain, two buried regions. A PN junction is formed between the body region and the high voltage well, wherein the PN junction is perpendicular to a channel direction. One buried region is formed in the epitaxial layer and has a first conductive type, wherein an inner side boundary thereof is located between the drain and the PN junction. The other buried region is formed in the substrate and in the epitaxial layer and has a second conductive type, wherein an inner side boundary thereof is located between the drain and the PN junction. The impurity concentration of the second buried region is sufficient to prevent the high voltage well between the PN junction and the drain from being completely depleted when the high-side power device is ON.

Abstract: A high-side device includes: a substrate, an epitaxial layer, a high voltage well, a body region, a gate, a source, a drain, and a buried region. A channel junction is formed between the body region and the high voltage well. The buried region is formed in the substrate and the epitaxial layer, and in a vertical direction, a part of the buried region is located in the substrate and another part of the buried region is located in the epitaxial layer. In the channel direction, an inner side boundary of the buried region is between the drain and the channel junction. An impurity concentration of a second conductive type of the buried region is sufficient to prevent the high voltage well between the channel junction and the drain from being completely depleted when the high-side power device operates in a conductive operation. A corresponding manufacturing method is also disclosed.

Abstract: Disclosed is an ESD protection device, comprising: a semiconductor substrate; a semiconductor buried layer located in the semiconductor substrate; an epitaxial semiconductor layer located on the semiconductor substrate and comprising a first doped region and a second doped region, wherein the semiconductor substrate and the first doped region are of a first doping type, the semiconductor buried layer, the epitaxial semiconductor layer and the second doped region are of a second doping type, the first doping type and the second doping type are opposite to each other, and the first doped region forms a plurality of interfaces with the epitaxial semiconductor layer. The disclosure improves protection performance and maximum current bearing capacity without increasing parasitic capacitance of the ESD protection device.

Abstract: A semiconductor device—e.g., a super junction power MOSFET—includes a number of columns of one type of dopant formed in a region of another type of dopant. Generally speaking, the columns are modulated in some manner. For example, the widths (e.g., diameters) of some columns are greater than the widths of other columns.

Abstract: On a front surface of an n+-type SiC substrate becoming a drain region, an n?-type drift layer, a p-type base layer, and an n+-type source layer are sequentially formed by epitaxial growth. In the n+-type source layer, the p+-type contact region is selectively provided. A trench is provided penetrating the n+-type source layer and the p-type base layer in the depth direction and reaching the n?-type drift layer. In the trench, a gate electrode is provided via a gate insulating film. A width between adjacent trenches is, for example, 1 ?m or less. A depth of the trench is, for example, 1 ?m or less. The width is narrow whereby substantially the entire p-type base layer forms a channel. A cell includes a FinFET structure in which one channel is sandwiched between MOS gates on both side. Thus, ON resistance may be reduced and decreased reliability may be prevented.

Abstract: A method for manufacturing a semiconductor device includes the steps of: determining a first design dimension of a gate electrode of a selection MISFET, a second design dimension of a sidewall insulating film, and initial setting conditions for ion implantation for a high-concentration semiconductor region; forming the gate electrode; measuring a first processed dimension of the gate electrode; implanting ions to form a low-concentration semiconductor region at each end of the gate electrode; forming the sidewall insulating film over a sidewall of the gate electrode; measuring a second processed dimension of the sidewall insulating film; and implanting ions to form a high-concentration semiconductor region. In the former implantation step, execution conditions to the initial setting conditions are reset according to a deviation of the first processed dimension from the first design dimension and a deviation of the second processed dimension from the second design dimension, and the step is executed.

Abstract: Disclosed is a transistor device and a method for producing a transistor device. The transistor device includes: a source region, a drift region, and a body region arranged between the source region and the drift region; a gate electrode adjacent the body region and dielectrically insulated from the body region by a gate dielectric; and a field electrode adjacent the drift region and dielectrically insulated from the drift region by a field electrode dielectric. The field electrode includes at least two layers of different electrically conductive materials.

Abstract: A high-side device includes: a substrate, an epitaxial layer, a high voltage well, a body region, a gate, a source, a drain, and a buried region. A channel junction is formed between the body region and the high voltage well. The buried region is formed in the substrate and the epitaxial layer, and in a vertical direction, a part of the buried region is located in the substrate and another part of the buried region is located in the epitaxial layer. In the channel direction, an inner side boundary of the buried region is between the drain and the channel junction. An impurity concentration of a second conductive type of the buried region is sufficient to prevent the high voltage well between the channel junction and the drain from being completely depleted when the high-side power device operates in a conductive operation. A corresponding manufacturing method is also disclosed.

Abstract: Vertical sense devices in vertical trench MOSFET. In accordance with an embodiment of the present invention, an electronic circuit includes a vertical trench metal oxide semiconductor field effect transistor configured for switching currents of at least one amp and a current sensing field effect transistor configured to provide an indication of drain to source current of the MOSFET. A current sense ratio of the current sensing FET is at least 15 thousand and may be greater than 29 thousand.

Abstract: A printhead substrate, comprising an electrothermal transducer configured to heat a printing material, a first DMOS transistor configured to drive the electrothermal transducer, a MOS structure forming an anti-fuse element, a second DMOS transistor configured to write information in the anti-fuse element by causing an insulation breakdown of an insulating film of the MOS structure, and a driving unit consisted of at least one MOS transistor and configured to drive the second DMOS transistor.

Abstract: A semiconductor device includes a substrate, first and second body regions, a well region, a source region, a drain region, and first and second doped regions. The first and second body regions are disposed in first and second regions respectively. The well region is disposed in the first and second regions and between the first and second body regions. First and second portions of the source region are disposed in the first and second body regions respectively. The drain region is disposed on the well region. The first doped region is disposed in the well region. The second doped region is disposed on the first doped region. A first portion of the first doped region and a first portion of the second doped region are disposed in the well region of the first region and extend toward the first body region and out of the well region.

Abstract: A laterally diffused metal-oxide semiconductor field-effect transistor, comprising a substrate, a first conductivity type well region, a second conductivity type well region, a drain electrode in the first conductivity type well region, a source electrode and a body region in the second conductivity type well region, and a gate electrode arranged across surfaces of the first conductivity type well region and the second conductivity type well region, and also comprising a floating layer ring arranged on the top of the first conductivity type well region and located between the gate electrode and the drain electrode and a plurality of groove polysilicon electrodes running through the floating layer ring and stretching into the first conductivity type well region.

Abstract: A high voltage MOS device includes: a first drift region with a first conductive type, a body region with a second conductive type, plural second drift regions with the second conductive type, a gate, a source region with the first conductive type, a drain with the first conductive type, and a body contact region with the second conductive type. The plural second drift regions contact the body region along the lateral direction, and are located separately in the width direction. Any neighboring two second drift regions do not contact each other. Each of the second drift regions is separated from the drain by the first drift region.

Abstract: A method for fabricating semiconductor device includes the steps of: forming a first trench in a substrate; forming a first shallow trench isolation (STI) in the first trench; forming a first patterned mask on the substrate; and using the first patterned mask to remove part of the first STI for forming a second trench and remove part of the substrate for forming a third trench. Preferably, a bottom surface of the third trench is lower than a bottom surface of the second trench.

Abstract: Methods for forming a fin field effect transistor (FinFET) device structure are provided. The method includes providing a first fin structure and a second fin structure extending above a substrate and forming an isolation structure over the substrate, and the an upper portion of the first fin structure and an upper portion of the second fin structure protrudes from the isolation structure. The method also includes forming a first transistor and a second transistor on the first fin structure and the second fin structure, and the first transistor includes a first gate dielectric layer. The method further includes forming an inter-layer dielectric (ILD) structure between the first transistor and the second transistor, and a portion of the first gate dielectric layer above the isolation structure is in direct contact with a sidewall of the ILD structure.