Abstract: Techniques are disclosed herein for creating metal bitlines (BLs) in stacked wafer memory. Using techniques described herein, metal BLs are created on a bottom surface of a wafer. The metal BLs can be created using different processes. In some configurations, a salicide process is utilized. In other configurations, a damascene process is utilized. Using metal reduces the resistance of the BLs as compared to using non-metal diffused BLs. In some configurations, wafers are stacked and bonded together to form three-dimensional memory structures.

Abstract: A semiconductor device includes a substrate, a bit line conductive layer disposed on the substrate and extending in a first lateral direction substantially parallel to a surface of the substrate, first and second channel structures disposed on the bit line conductive layer to be spaced apart from each other in the first lateral direction, first and second gate dielectric layers disposed on side surfaces of the first and second channel structures over the substrate, first and second gate line conductive layers disposed on the first and second gate dielectric layers, respectively, the first and second gate line conductive layers common to the first and second channel structures, respectively, and extending in a second lateral direction perpendicular to the first lateral direction and substantially parallel to the surface of the substrate, and first and second storage node electrode layers disposed over the first and second channel structures, respectively.

Abstract: Methods, systems, and devices for a memory device with multiplexed digit lines are described. In some cases, a memory cell of the memory device may include a storage component and a selection component that includes two transistors. A first transistor may be coupled with a word line and a second transistor may be coupled with a select line to selectively couple the memory cell with a digit line. The selection component, in conjunction with a digit line multiplexing component, may support a sense component common to a set of digit lines. In some cases, the digit line of the set may be coupled with the sense component during a read operation, while the remaining digit lines of the set are isolated from the sense component.

Abstract: A semiconductor device is provided which includes a first control circuit including a first transistor in a silicon substrate channel, a second control circuit provided over the first control circuit, a memory circuit provided over the second control circuit, and a global bit line and an inverted global bit line that have a function of transmitting a signal between the first control circuit and the second control circuit. The first control circuit includes a sense amplifier circuit including an input terminal and an inverted input terminal. In a first period for reading data from the memory circuit to the first control circuit, the second control circuit controls whether the global bit line and the inverted global bit line from which electric charge is discharged are charged or not in accordance with the data read from the memory circuit.

Abstract: Reliability and performance of a semiconductor device are improved. First, a first mask pattern is formed on the semiconductor substrate in each of first to third regions. Next, a second mask pattern made of a material that is different from a material configuring the first mask pattern is formed on a side surface of the first mask pattern and on the semiconductor substrate in each of the first to third regions. Next, by an anisotropic etching process performed to the semiconductor substrate, a plurality of fins protruding from the recessed upper surface of the semiconductor substrate are formed. In the manner, fins each having a different structure from that of a fin in the first region can be formed in the second and third regions.

Abstract: A method for forming a semiconductor memory structure includes forming a hard mask layer over a semiconductor substrate, etching the hard mask layer to form first mask patterns and second mask patterns, transferring the first and second mask patterns to the substrate to form semiconductor blocks, and thinning down the second mask element. After thinning down the second mask element, the thickness of the second mask elements is less than the thickness of the first mask elements. The method also includes forming a first capping layer to laterally extend over the first mask patterns and the second mask patterns, and etching the first capping layer and the second mask pattern to form contact openings.

Abstract: A semiconductor memory structure includes a semiconductor substrate including an active region and a chop region. The semiconductor memory structure also includes an isolation structure disposed in the chop region, a first gate structure extending at least through the isolation structure in the chop region, and a second gate structure extending at least through the active region. The semiconductor memory structure also includes a doped region disposed in the active region. A first distance between the doped region and the first gate structure is shorter than a second distance between the doped region and the second gate structure.

Abstract: An embedded dynamic random-access memory cell includes a wordline to supply a gate signal, a selector thin-film transistor (TFT) above the wordline and that includes an active layer and is configured to control transfer of a memory state of the memory cell between a first region and a second region of the active layer in response to the gate signal, a bitline to transfer the memory state and coupled to and above the first region of the active layer, a storage node coupled to and above the second region of the active layer, and a metal-insulator-metal capacitor coupled to and above the storage node and configured to store the memory state. In an embodiment, the wordline is formed in a back end of line process for interconnecting logic devices formed in a front end of line process below the wordline, and the selector TFT is formed in a thin-film process.

Abstract: Provided is a dynamic random access memory. A plurality of isolation structures is disposed in a substrate to define a plurality of active regions arranged along a first direction. The substrate has a trench extended along the first direction and passing through the plurality of isolation structures and the plurality of active regions. A buried word line is disposed in the trench. A plurality of gate dielectric layers is disposed in the trench of the plurality of active regions to surround and cover the buried word line. A cap layer covers the buried word line. The height of the top surface of the second side of the buried word line is lower than the height of the top surface of the first side of the buried word line passing through the plurality of active regions and the plurality of isolation structures.

Abstract: A split gate semiconductor device includes a trench gate having a first electrode region and a second electrode region that are separated from each other by a gate oxide layer and an adjacent dielectric layer. The boundary of the gate oxide layer and the dielectric layer is curved to avoid a sharp corner where the gate oxide layer meets the sidewalls of the trench.

Abstract: Fabrication method for a semiconductor memory device and structure are provided, which includes: providing at least two mask layers over a pair of fin structures extended above a substrate, wherein a first mask layer of the at least two mask layers is orthogonal to a second mask layer of the at least two mask layers; and patterning the pair of fin structures to define a pass-gate transistor, wherein the first mask layer facilitates removing of a portion of a first fin structure of the pair of fin structures to define a first pass-gate fin portion of the pass-gate transistor, and the second mask layer protects a second fin structure of the pair of fin structures to define a second pass-gate fin portion of the pass-gate transistor.

Abstract: A touch panel includes a dummy electrode capable of protecting a circuit included in the touch panel for shielding against static electricity.

Abstract: An integrated circuit is disclosed that includes a single channel device having a first portion of a single shared heterostructure overlying a substrate structure in a single channel device area, and a gate contact that is in contact with the first portion of the single shared heterostructure. The integrated circuit also includes a multichannel device comprising a second portion of the single shared heterostructure overlying the substrate structure in a multichannel device area, a barrier layer overlying the second portion of the single shared heterostructure, and a superlattice structure overlying the barrier layer, the superlattice structure comprising a plurality of heterostructures. An isolation region in the single shared heterostructure electrical isolates the single channel device from the multichannel device.

Abstract: In a semiconductor device, a support wall is formed between storage nodes to more effectively prevent leaning of a capacitor, and the storage nodes are formed using a damascene process, which may increase a contact area between each storage node and a storage node contact.

Abstract: A semiconductor device may include, but is not limited to, a semiconductor substrate having a first gate groove; a first fin structure underneath the first gate groove; a first diffusion region in the semiconductor substrate, the first diffusion region covering an upper portion of a first side of the first gate groove; and a second diffusion region in the semiconductor substrate. The second diffusion region covers a second side of the first gate groove. The second diffusion region has a bottom which is deeper than a top of the first fin structure.

Abstract: A method for forming a trench MOSFET includes doping a body region of the trench MOSFET in multiple ion implantation steps each having different ion implantation energy. The method further comprises etching the trench to a depth of about 1.7 ?m.

Abstract: Method for fabricating MOSFET integrated with Schottky diode (MOSFET/SKY) is disclosed. Gate trench is formed in an epitaxial layer overlaying semiconductor substrate, gate material is deposited therein. Body, source, dielectric regions are successively formed upon epitaxial layer and the gate trench. Top contact trench (TCT) is etched with vertical side walls defining Schottky diode cross-sectional width SDCW through dielectric and source region defining source-contact depth (SCD); and partially into body region by total body-contact depth (TBCD). A heavily-doped embedded body implant region (EBIR) of body-contact depth (BCD)<TBCD is created into side walls of TCT and beneath SCD. An embedded Shannon implant region (ESIR) is created into sub-contact trench zone (SCTZ) beneath TCT floor. A metal layer is formed in contact with ESIR, body and source region. The metal layer also fills TCT and covers dielectric region thus completing the MOSFET/SKY with only one-time etching of its TCT.

Abstract: A method of fabricating semiconductor devices having metal gate electrodes includes forming an insulating layer on a semiconductor substrate having a first region and a second region. The insulating layer is formed to include an interlayer insulating layer and a gate insulation layer. The interlayer insulating layer has first and second grooves respectively disposed in the first and second regions, and the gate insulation layer covers at least bottom surfaces of the first and second grooves. A laminated metal layer is formed on the substrate having the insulating layer. A planarization layer having non-photo sensitivity is formed on the laminated metal layer. The planarization layer in the first region is selectively removed using a dry etching process to expose the laminated metal layer in the first region and to form a planarization layer pattern covering the laminated metal layer in the second region.

Abstract: A semiconductor device has a semiconductor substrate with a plurality of transistor cell regions. Each transistor cell region includes a plurality of trenches disposed in the semiconductor substrate, a well region between the plurality of trenches, and a source region of a MOSFET in the well region. A source electrode of the MOSFET is in contact with a top surface of the source region in each of the plurality of transistor cell regions. The source electrode is in contact with a part of a main surface of the semiconductor substrate so as to form a Schottky junction in a Schottky cell region disposed between the plurality of transistor cell regions. The Schottky junction is lower than a portion of the main surface between the Schottky junction and one of the transistor cell regions.

Abstract: A semiconductor device may include, but is not limited to, a semiconductor substrate having a device isolation groove defining first to fourth device formation portions. The second device formation portion is separated from the first device formation portion. The third device formation portion extends from the first device formation portion. The third device formation portion is separated from the second device formation portion. The fourth device formation portion extends from the second device formation portion. The fourth device formation portion is separated from the first and third device formation portions. The third and fourth device formation portions are positioned between the first and second device formation portions.

Abstract: Some embodiments include methods of forming contacts. A row of projections may be formed over a semiconductor substrate. The projections may include a plurality of repeating components of an array, and a terminal projection. The terminal projection may have a sacrificial material spaced from semiconductor material of the substrate by a dielectric structure. An electrically conductive line may be formed along the row. The line may wrap around an end of the terminal projection and bifurcate into two branches that are along opposing sides of the repeating components. The individual branches may have regions spaced from the sacrificial material by segments of gate dielectric. The sacrificial material may be removed, together with the segments of gate dielectric, to form a contact opening. An electrically conductive contact may be formed within the contact opening and directly against the regions of the branches.

Abstract: Systems and methods associated with semiconductor articles are disclosed, including forming a first layer of material on a substrate, etching trenches within regions defining a passive element in the first layer, forming metal regions on sidewalls of the trenches, and forming a region of dielectric or polymer material over or in the substrate. Moreover, an exemplary method may also include forming areas of metal regions on the sidewalls of the trenches such that planar strip portions of the areas form electrically conductive regions of the passive element(s) that are aligned substantially perpendicularly with respect to a primary plane of the substrate. Other exemplary embodiments may comprise various articles or methods including capacitive and/or inductive aspects, Titanium- and/or Tantalum-based resistive aspects, products, products by processes, packages and composites consistent with one or more aspects of the innovations set forth herein.

Abstract: A method of forming a device in each of vertical trench gate MOSFET region and control lateral planar gate MOSFET region of a semiconductor substrate is disclosed. A trench is formed in the substrate in the vertical trench gate MOSFET region, a first gate oxide film is formed along the internal wall of the trench, and the trench is filled with a polysilicon film. A LOCOS oxide film is formed in a region isolating the devices. A second gate oxide film is formed on the substrate in the lateral planar gate MOSFET region. Advantages are that number of steps is suppressed, the gate threshold voltage of an output stage MOSFET is higher than the gate threshold voltage of a control MOSFET, the thickness of the LOCOS oxide film does not decrease, and no foreign object residue remains inside the trench.

Abstract: A method of manufacturing a semiconductor device includes forming an insulating isolation portion in a groove of a substrate, forming a projection portion in which an upper portion of the insulating isolation portion projects from a principal surface of the substrate, forming a sidewall spacer covering a side surface of the projection portion and part of the principal surface of the substrate along the side surface of the projection portion, and forming a first trench in the substrate by etching the substrate using the sidewall spacer as a mask.

Abstract: A body layer is formed in an epitaxial layer and a gate electrode formed in a trench in the body and epitaxial layer. A gate insulator is disposed along a sidewall of the gate electrode between the gate electrode and the source, between the gate electrode and the P-body and between the gate electrode and the epitaxial layer. A cap insulator is disposed on top of the gate electrode. A doped spacer is disposed along a sidewall of the source and a sidewall of the gate insulator. The body layer next to the polysilicon spacer is etched back below the bottom of the polysilicon spacer. Dopants are diffused from the spacer to form the source region.

Abstract: In methods of manufacturing a DRAM device, a buried-type gate is formed in a substrate. A capping insulating layer pattern is formed on the buried-type gate. A conductive layer pattern filling up a gap between portions of the capping insulating layer pattern, and an insulating interlayer covering the conductive layer pattern and the capping insulating layer pattern are formed. The insulating interlayer, the conductive layer pattern, the capping insulating layer pattern and an upper portion of the substrate are etched to form an opening, and a first pad electrode making contact with a first pad region. A spacer is formed on a sidewall of the opening corresponding to a second pad region. A second pad electrode is formed in the opening. A bit line electrically connected with the second pad electrode and a capacitor electrically connected with the first pad electrode are formed.

Abstract: Provided is a semiconductor device in which on-resistance is largely reduced based on a new principle of operation. In the semiconductor device, if an embedded electrode is at negative potential, a depletion layer is formed from a trench to a neighboring trench so that a channel is turned off. If the embedded electrode is at a positive potential, the depletion layer is not formed in every region between the neighboring trenches so that the channel is turned on.

Abstract: Method for fabricating MOSFET integrated with Schottky diode (MOSFET/SKY) is disclosed. Gate trench is formed in an epitaxial layer overlaying semiconductor substrate, gate material is deposited therein. Body, source, dielectric regions are successively formed upon epitaxial layer and the gate trench. Top contact trench (TCT) is etched with vertical side walls defining Schottky diode cross-sectional width SDCW through dielectric and source region defining source-contact depth (SCD); and partially into body region by total body-contact depth (TBCD). A heavily-doped embedded body implant region (EBIR) of body-contact depth (BCD)<TBCD is created into side walls of TCT and beneath SCD. An embedded Shannon implant region (ESIR) is created into sub-contact trench zone (SCTZ) beneath TCT floor. A metal layer is formed in contact with ESIR, body and source region. The metal layer also fills TCT and covers dielectric region thus completing the MOSFET/SKY with only one-time etching of its TCT.

Abstract: The present invention belongs to the technical field of semiconductor device manufacturing and specifically relates to a method for manufacturing a tunneling field effect transistor with a U-shaped channel. The U-shaped channel can effectively extend the transistor channel length, restrain the generation of leakage current in the transistor, and decrease the chip power consumption. The method for manufacturing a tunneling field effect transistor with a U-shaped channel put forward in the present invention is capable of realizing an extremely narrow U-shaped channel, overcoming the alignment deviation introduced by photoetching, and improving the chip integration degree.

Abstract: A semiconductor device includes a first-conductivity-type semiconductor layer, a base region of a second-conductivity-type formed in an upper portion of the first-conductivity-type semiconductor layer, first though third trenches penetrating through the base region and reaching to the first-conductivity-type semiconductor layer, the first through third trenches being linked to one another, a source interconnect layer buried in the first through third trenches, the source interconnect layer including a protruding portion, a gate electrode buried in the first trench and the third trench, and formed over the source interconnect layer, a source metal contacting the protruding portion of the source interconnect layer, and a gate metal contacting the gate electrode in the third trench. A contact face between the source metal and the protruding portion at the second trench is formed higher than a contact face between the gate metal and the gate electrode at the third trench.

Abstract: A trench MOSFET comprising source regions having a doping profile of a Gaussian-distribution along the top surface of epitaxial layer and floating dummy cells formed between edge trench and active area is disclosed. A SBR of n region existing at cell corners renders the parasitic bipolar transistor difficult to turn on, and the floating dummy cells having no parasitic bipolar transistor act as buffer cells to absorb avalanche energy when gate bias is increasing for turning on channel, therefore, the UIS failure issue is avoided and the avalanche capability of the trench MOSFET is enhanced.

Abstract: A method for fabricating vertical surround gate structures in semiconductor device arrays. The method includes forming pillars separated by vertical and horizontal trenches on a substrate. Forming a gate layer over the pillars and trenches such that the gate layer forms gate trenches in the horizontal trenches. The method includes forming fillers within the gate trenches, and planarizing the gate layer and fillers. The method also includes successively etching a first portion of the gate layer, removing the fillers, and etching a second portion of the gate layer.

Abstract: A method for fabricating vertical surround gate structures in semiconductor device arrays. The method includes forming pillars separated by vertical and horizontal trenches on a substrate. Forming a gate layer over the pillars and trenches such that the gate layer forms gate trenches in the horizontal trenches. The method includes forming fillers within the gate trenches, and planarizing the gate layer and fillers. The method also includes successively etching a first portion of the gate layer, removing the fillers, and etching a second portion of the gate layer.

Abstract: A method of forming a semiconductor device includes the following processes. A first groove is formed in a semiconductor substrate. A first conductive film is formed in the first groove and over the semiconductor substrate. The first conductive film is planarized over the semiconductor substrate. The planarized first conductive film is selectively etched to have the planarized first conductive film remain in a lower portion of the first groove.

Abstract: In one general aspect, an apparatus can include a shield dielectric disposed within a trench aligned along an axis within an epitaxial layer of a semiconductor, and a shield electrode disposed within the shield dielectric and aligned along the axis. The apparatus can include a first inter-poly dielectric having a portion intersecting a plane orthogonal to the axis where the plane intersects the shield electrode, and a second inter-poly dielectric having a portion intersecting the plane and disposed between the first inter-poly dielectric and the shield electrode. The apparatus can also include a gate dielectric having a portion disposed on the first inter-poly dielectric.

Abstract: A semiconductor memory device includes a first conductive line, a second conductive line crossing over the first conductive line, a resistance variation part disposed at a position in which the second conductive line intersects with the first conductive line and electrically connected to the first conductive line and the second conductive line and a mechanical switch disposed between the resistance variation part and the second conductive line. The mechanical switch includes a nanotube.

Abstract: A closed cell trench MOSFET structure having a drain region of a first conductivity type, a body of a second conductivity type, a trenched gate, and a plurality of source regions of the first conductivity type is provided. The body is located on the drain region. The trenched gate is located in the body and has at least two stripe portions and a cross portion. A bottom of the stripe portions is located in the drain region and a bottom of the cross portion is in the body. The source regions are located in the body and at least adjacent to the stripe region of the trenched gate.

Abstract: A shielding structure for a semiconductor device includes a plurality of trenches. The trenches include passivation liners and shield electrodes, which are formed therein. In one embodiment, the shielding structure is placed beneath a control pad. In another embodiment, the shielding structure is placed beneath a control runner.

Abstract: A memory array structure and a method for forming the same are provided. The memory array structure comprises: a substrate; a plurality of memory cells, each memory cell including a vertical transistor, of which a gate structure is formed in a first trench extending in a first direction; a plurality of word lines in the first direction, each word line formed in the first trench; a plurality of bit lines in a second direction, each bit line formed in lower sides of a semiconductor pillars; a plurality of body lines in the first direction, each body line having a first portion formed on the gate electrodes and a second portion covering a part of a top surface of semiconductor pillar for providing a substrate contact to vertical channel regions; and a plurality of data storage device contacts.

Abstract: The present invention provides a power transistor device including a substrate, an epitaxial layer, a dopant source layer, a doped drain region, a first insulating layer, a gate structure, a second insulating layer, a doped source region, and a metal layer. The substrate, the doped drain region, and the doped source region have a first conductive type, while the epitaxial layer has a second conductive type. The epitaxial layer is formed on the substrate and has at least one through hole through the epitaxial layer. The first insulating layer, the gate structure, and the second insulating layer are formed sequentially on the substrate in the through hole. The doped drain region and doped source region are formed in the epitaxial layer at one side of the through hole. The metal layer is formed on the epitaxial layer and extends into the through hole to contact the doped source region.

Abstract: Some embodiments include methods of forming contacts. A row of projections may be formed over a semiconductor substrate. The projections may include a plurality of repeating components of an array, and a terminal projection. The terminal projection may have a sacrificial material spaced from semiconductor material of the substrate by a dielectric structure. An electrically conductive line may be formed along the row. The line may wrap around an end of the terminal projection and bifurcate into two branches that are along opposing sides of the repeating components. The individual branches may have regions spaced from the sacrificial material by segments of gate dielectric. The sacrificial material may be removed, together with the segments of gate dielectric, to form a contact opening. An electrically conductive contact may be formed within the contact opening and directly against the regions of the branches.

Abstract: The process methods and structures mentioned above for creating a trench MOSFET enables self-aligned contacts to be formed to allow decreasing pitch size for trench MOSFET. The self-aligned contacts are formed by etching exposed silicon areas without using lithographical mask and alignment. As a result, the allowance for alignment can be saved and the pitch size can be decreased.

Abstract: A semiconductor device and a method for manufacturing the same are disclosed. A recess gate structure is formed between an overlapping region between a gate and a source/drain so as to suppress increase in gate induced drain leakage (GIDL), and a gate insulation film is more thickly deposited in a region having weak GIDL, thereby reducing GIDL and thus improving refresh characteristics due to leakage current.

Abstract: A semiconductor device includes a transistor that has a trench formed in an element forming region of a substrate, a gate insulating film formed on side faces and a bottom face of the trench, a gate electrode formed on the gate insulating film so as to bury the trench, a source region formed on one side in the gate longitude direction, which is formed on the surface of the substrate, and a drain region formed on the other side in the gate longitude direction. Here, the gate electrode is formed so as to be exposed also on the substrate outside the trench, and the gate electrode is disposed so as to cover upper portions of both ends of the trench and so as to form at least one concave portion having a depth reaching the substrate in a center portion.

Abstract: A method for fabricating a semiconductor device includes forming a plurality of trenches using a first mask. The trenches include source pickup trenches located in outside a termination area and between two adjacent active areas. First and second conductive regions separated by an intermediate dielectric region are formed using a second mask. A first electrical contact to the first conductive region and a second electrical contact to the second conductive region are formed using a third mask and forming a source metal region. Contacts to a gate metal region are formed using a fourth mask. A semiconductor device includes a source pickup contact located outside a termination region and outside an active region of the device.

Abstract: A semiconductor device for use in a power supply circuit has first and second MOSFETS. The source-drain path of one of the MOSFETS are coupled to the source-drain path of the other, and a load element is coupled to a connection node of the source-drain paths. The second MOSFET is formed on a semiconductor substrate with a Schottky barrier diode. First gate electrodes of the second MOSFET are formed in trenches in a first region of the semiconductor substrate, while second gate electrodes of the second MOSFET are formed in trenches in a second region of the semiconductor substrate. The first and second gate electrodes are electrically connected together. Portions of the Schottky barrier diode are formed between adjacent ones of the second gate electrodes. A center-to-center spacing between adjacent first gate electrodes is smaller than a center-to-center spacing between adjacent second gate electrodes.

Abstract: To provide an active region having first and second diffusion layers positioned at both sides of a gate trench and a third diffusion layer formed on a bottom surface of the gate trench, first and second memory elements connected to the first and second diffusion layers, respectively, a bit line connected to the third diffusion layer, a first gate electrode that covers a first side surface of the gate trench via a gate dielectric film and forms a channel between the first diffusion layer and the third diffusion layer, and a second gate electrode that covers a second side surface of the gate trench via a gate dielectric film and forms a channel between the second diffusion layer and the third diffusion layer. According to the present invention, because separate transistors are formed on both side surfaces of a gate trench, two times of conventional integration can be achieved.

Abstract: A semiconductor structure having U-shaped transistors includes source/drain regions at the tops of pairs of pillars defined by crossing trenches in the substrate. One pillar is connected to the other pillar in the pair by a ridge that extends above the surrounding trenches. The ridge and lower portions of the pillars define U-shaped channels on opposite sides of the U-shaped structure, facing a gate structure in the trenches on those opposite sides, forming a two sided surround transistor. Optionally, the space between the pillars of a pair is also filled with gate electrode material to define a three-sided surround gate transistor. One of the source/drain regions of each pair extending to a digit line and the other extending to a memory storage device, such as a capacitor. Methods of forming semiconductor structures are also disclosed.

Abstract: In one embodiment, the present invention includes a semiconductor power device. The semiconductor power device comprises a trenched gate and a trenched field region. The trenched gate is disposed vertically within a trench in a semiconductor substrate. The trenched field region is disposed vertically within the trench and below the trenched gate. A lower portion of the trenched field region tapers to disperse an electric field.

Abstract: A fabricating method of an insulator for replacing a gate structure in a substrate by the insulator. The fabricating method includes the step of providing a substrate including a first buried gate structure. The first buried structure includes a first trench embedded in the substrate and a first gate filling in the first trench. The first trench has a first depth. Then, the first gate of the first buried structure is removed. Later, the substrate under the first trench is etched to elongate the depth of the first trench from the first depth to a third depth. Finally, an insulating material fills in the first trench with the third depth to form an insulator of the present invention.