Abstract: A semiconductor device includes a plurality of first trenches having a first depth formed in a semiconductor substrate, a plurality of second trenches having a second depth formed in the semiconductor substrate, wherein the second depth is different from the first depth and the second trenches are formed between the first trenches, a plurality of isolation layers formed at the plurality of first trenches and the plurality of second trenches, wherein the isolation layers have upper portions formed above the semiconductor substrate, and a plurality of memory cells formed over the semiconductor substrate between the isolation layers.

Abstract: This invention discloses semiconductor device that includes a top region and a bottom region with an intermediate region disposed between said top region and said bottom region with a controllable current path traversing through the intermediate region. The semiconductor device further includes a trench with padded with insulation layer on sidewalls extended from the top region through the intermediate region toward the bottom region wherein the trench includes randomly and substantially uniformly distributed nano-nodules as charge-islands in contact with a drain region below the trench for electrically coupling with the intermediate region for continuously and uniformly distributing a voltage drop through the current path.

Abstract: A semiconductor device includes, on a semiconductor substrate, an active region surrounded by an STI region, a gate trench formed in one direction transverse to the active region, a gate insulating film formed on a side surface of the gate trench, an insulating film formed on a bottom of the gate trench and thicker than the gate insulating film, and a gate electrode having at least a part of the gate electrode formed in the gate trench. Portions of the semiconductor substrate present in the active region and located on both sides of the gate trench in an extension direction of the gate trench function as a source region and a drain region, respectively. A portion of the semiconductor substrate located between the side surface of the active region (the side of the STI region) and the side surface of the gate trench functions as a channel region.

Abstract: A common cut mask is employed to define a gate pattern and a local interconnect pattern so that local interconnect structures and gate structures are formed with zero overlay variation relative to one another. A local interconnect structure may be laterally spaced from a gate structure in a first horizontal direction, and contact another gate structure in a second horizontal direction that is different from the first horizontal direction. Further, a gate structure may be formed to be collinear with a local interconnect structure that adjoins the gate structure. The local interconnect structures and the gate structures are formed by a common damascene processing step so that the top surfaces of the gate structures and the local interconnect structures are coplanar with each other.

Abstract: Trenches are formed into semiconductive material. Masking material is formed laterally over at least elevationally inner sidewall portions of the trenches. Conductivity modifying impurity is implanted through bases of the trenches into semiconductive material there-below. Such impurity is diffused into the masking material received laterally over the elevationally inner sidewall portions of the trenches and into semiconductive material received between the trenches below a mid-channel portion. An elevationally inner source/drain is formed in the semiconductive material below the mid-channel portion. The inner source/drain portion includes said semiconductive material between the trenches which has the impurity therein. A conductive line is formed laterally over and electrically coupled to at least one of opposing sides of the inner source/drain. A gate is formed elevationally outward of and spaced from the conductive line and laterally adjacent the mid-channel portion. Other embodiments are disclosed.

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: In one embodiment, a nonvolatile semiconductor memory device includes a substrate, and a well region formed in the substrate. The device further includes device regions formed in the well region and defined by isolation trenches formed in the well region, the device regions extending in a first direction parallel to a principal surface of the substrate, and being adjacent to one another in a second direction that is perpendicular to the first direction. The device further includes isolation insulators buried in the isolation trenches to isolate the device regions from one another. The device further includes floating gates disposed on the device regions via gate insulators, and a control gate disposed on the floating gates via an intergate insulator. The device further includes first diffusion suppressing layers formed inside the respective device regions to divide each of the device regions into an upper device region and a lower device region.

Abstract: A semiconductor device having a buried gate that can realize a reduction in gate-induced drain leakage is presented. The semiconductor device includes a semiconductor substrate, a buried gate, and a barrier layer. The semiconductor substrate has a groove. The buried gate is formed in a lower portion of the groove and has a lower portion wider than an upper portion. The barrier layer is formed on sidewalls of the upper portion of the buried gate.

Abstract: A method for forming a field effect transistor (FET) includes forming a dummy gate on a top semiconductor layer of a semiconductor on insulator substrate; forming source and drain regions in the top semiconductor layer, wherein the source and drain regions are located in the top semiconductor layer on either side of the dummy gate; forming a supporting material over the source and drain regions adjacent to the dummy gate; removing the dummy gate to form a gate opening, wherein a channel region of the top semiconductor layer is exposed through the gate opening; thinning the channel region of the top semiconductor layer through the gate opening; and forming gate spacers and a gate in the gate opening over the thinned channel region.

Abstract: A method of forming an electronic device including forming a first trench in a workpiece including a substrate, the first trench having side walls and a bottom surface extending for a width between the side walls and forming a charge-storage layer along the side walls and bottom surface of the first trench. The method further includes implanting ions within the substrate underlying the bottom surface of the first trench to form an implant region and annealing the implant region, wherein after annealing, the implant region extends the width of the bottom surface and along a portion of the side walls.

Abstract: Affords Group III nitride semiconductor devices in which the leakage current from the Schottky electrode can be reduced. In a high electron mobility transistor 11, a supporting substrate 13 is composed of AlN, AlGaN, or GaN, specifically. An AlYGa1?YN epitaxial layer 15 has a full-width-at-half maximum of (0002) plane XRD of 150 sec or less. A GaN epitaxial layer 17 is provided between the gallium nitride supporting substrate and the AlYGa1?YN epitaxial layer (0<Y?1). A Schottky electrode 19 is provided on the AlYGa1?YN epitaxial layer 15. The Schottky electrode 19 constitutes a gate electrode of the high electron mobility transistor 11. The source electrode 21 is provided on the gallium nitride epitaxial layer 15. The drain electrode 23 is provided on the gallium nitride epitaxial layer 15.

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 memory array includes a plurality of memory cells formed on a semiconductor substrate. Individual of the memory cells include first and second field effect transistors respectively comprising a gate, a channel region, and a pair of source/drain regions. The gates of the first and second field effect transistors are hard wired together. A conductive data line is hard wired to two of the source/drain regions. A charge storage device is hard wired to at least one of the source/drain regions other than the two. Other aspects and implementations are contemplated, including methods of fabricating memory arrays.

Abstract: A semiconductor device and fabrication methods are disclosed. The device includes a plurality of gate electrodes formed in trenches located in an active region of a semiconductor substrate. A first gate runner is formed in the substrate and electrically connected to the gate electrodes, wherein the first gate runner surrounds the active region. A second gate runner is connected to the first gate runner and located between the active region and a termination region. A termination structure surrounds the first and second gate runners and the active region. The termination structure includes a conductive material in an insulator-lined trench in the substrate, wherein the termination structure is electrically shorted to a source or body layer of the substrate thereby forming a channel stop for the device.

Abstract: The present disclosure provides a method that includes forming a high k dielectric layer on a semiconductor substrate; forming a polysilicon layer on the high k dielectric layer; patterning the high k dielectric layer and polysilicon layer to form first and second dummy gates in first and second field effect transistor (FET) regions, respectively; forming an inter-level dielectric (ILD); applying a first CMP process to the semiconductor substrate, exposing the first and second dummy gates; removing the polysilicon from the first dummy gate, resulting in a first gate trench; forming a first metal electrode in the first gate trench; applying a second CMP process; forming a mask covering the first FET region and exposing the second dummy gate; thereafter removing the polysilicon from the second dummy gate, resulting in a second gate trench; forming a second metal electrode in the second gate trench; and applying a third CMP process.

Abstract: DRAM cell arrays having a cell area of less than about 4F2 comprise an array of vertical transistors with buried bit lines and vertical double gate electrodes. The buried bit lines comprise a silicide material and are provided below a surface of the substrate. The word lines are optionally formed of a silicide material and form the gate electrode of the vertical transistors. The vertical transistor may comprise sequentially formed doped polysilicon layers or doped epitaxial layers. At least one of the buried bit lines is non-orthogonal to at least one of the vertical gate electrodes of the vertical transistors.

Abstract: A semiconductor device has a well region formed of a first conductivity type semiconductor at a predetermined depth from a surface of a substrate, trenches formed in the well region, and a gate insulating film formed on surfaces of concave and convex portions of the trenches. A first gate electrode is embedded inside the trenches, and a second gate electrode is formed on the substrate in contact with the first gate electrode in regions of the concave and convex portions excluding vicinities of both ends of the trenches. Source and drain regions of a second conductivity type are formed from a part of a surface of the semiconductor so as to extend deeper in a side surface of the concave portion of each trench than in the surface of the convex portion of each trench and shallower than the depth of the well region.

Abstract: A semiconductor device includes a first conductivity type layer of a first conductivity type, a body layer of a second conductivity type formed on the first conductivity type layer, a gate trench passing through the body layer so that the deepest portion thereof reaches the first conductivity type layer, a source region of the first conductivity type formed around the gate trench on the surface layer portion of the body layer, a gate insulating film formed on the bottom surface and the side surface of the gate trench, and a gate electrode embedded in the gate trench through the gate insulating film, and the bottom surface of the gate electrode and the upper surface of the first conductivity type layer are flush with each other.

Abstract: A method for forming a buried split word line structure is provided. The method comprises the following steps. At first, a substrate having a trench therein is provided. Two liners are formed to a first thickness on sidewalls of the trench. Then, the trench is filled with a first insulating layer to a first height. The two liners are removed. Finally, a conductive material is deposited to a second height between and adjacent to the first insulating layer and the trench. Here, the first height is greater than the second height.

Abstract: A semiconductor device having a modified recess channel gate includes active regions defined by a device isolation layer and arranged at regular intervals on a semiconductor substrate, each active region extending in a major axis and a minor axis direction, a trench formed in each active region, the trench including a stepped bottom surface in the minor axis direction of the active region, and a recess gate formed in the trench.

Abstract: A method for forming an opening within a semiconductor material comprises forming a neck portion, a rounded portion below the neck portion and, in some embodiments, a protruding portion below the rounded portion. This opening may be filled with a conductor, a dielectric, or both. Embodiments to form a transistor gate, shallow trench isolation, and an isolation material separating a transistor source and drain are disclosed. Device structures formed by the method are also described.

Abstract: A semiconductor device having a saddle fin gate and a method for manufacturing the same are presented. The semiconductor device includes a semiconductor substrate, an isolation structure, and gates. The semiconductor substrate is defined with first grooves in gate forming areas. The isolation structure is formed in the semiconductor substrate and is defined with second grooves which expose front and rear surfaces of the gate forming areas. The gates are formed within the first grooves in the gate forming areas. Gates are also formed in the second grooves of the isolation structure to cover the exposed front and rear surfaces of the gate forming areas. The second grooves are wider at the lower portions that at the upper portions.

Abstract: One embodiment in accordance with the invention can include a semiconductor device that includes: a groove that is formed in a semiconductor substrate; bottom oxide films that are formed on both side faces of the groove; two charge storage layers that are formed on side faces of the bottom oxide films; top oxide films that are formed on side faces of the two charge storage layers; and a silicon oxide layer that is formed on the bottom face of the groove, and has a smaller film thickness than the top oxide films.

Abstract: A method for fabricating a floating gate memory device comprises using a buried diffusion oxide that is below the floating gate thereby producing an increased step height between the floating gate and the buried diffusion oxide. The increased step height can produce a higher GCR, while still allowing decreased cell size using a virtual ground array design.

Abstract: A power semiconductor structure with schottky diode is provided. In the step of forming the gate structure, a separated first polysilicon structure is also formed on the silicon substrate. Then, the silicon substrate is implanted with dopants by using the first polysilicon structure as a mask to form a body and a source region. Afterward, a dielectric layer is deposited on the silicon substrate and an open penetrating the dielectric layer and the first polysilicon structure is formed so as to expose the source region and the drain region below the body. The depth of the open is smaller than the greatest depth of the body. Then, a metal layer is filled into the open to electrically connect to the source region and the drain region.

Abstract: According to one embodiment, a semiconductor device includes a first and a second semiconductor layer of a first conductivity type, a third semiconductor layer of a second conductivity type, a source region of the first conductivity type, a first and a second main electrode, trench gates, a first and a second contact region. The third semiconductor layer is provided on the second semiconductor layer provided on the first semiconductor layer. The first main electrode is electrically connected to the first semiconductor layer. The second main electrode is electrically connected to the source region provided on the third semiconductor layer. The trench gates are provided from the third semiconductor layer to the second semiconductor layer. The first and second contact regions electrically connect the second main electrode and the third semiconductor layer. An opening area of the second contact hole is smaller than that of the first contact hole.

Abstract: The present invention discloses a transistor having the saddle fin structure. The saddle fin transistor of the present invention has a structure in which a landing plug contact region, particularly, a landing plug contact region on an isolation layer is elevated such that the landing plug contact SAC (Self Aligned Contact) fail can be prevented.

Abstract: A transistor gate forming method includes forming a metal layer within a line opening and forming a fill layer within the opening over the metal layer. The fill layer is substantially selectively etchable with respect to the metal layer. A transistor structure includes a line opening, a dielectric layer within the opening, a metal layer over the dielectric layer within the opening, and a fill layer over the metal layer within the opening. The metal layer/fill layer combination exhibits less intrinsic less than would otherwise exist if the fill layer were replaced by an increased thickness of the metal layer. The inventions apply at least to 3-D transistor structures.

Abstract: A nonvolatile semiconductor memory fabrication method including forming a first insulating film and a floating gate electrode material on a semiconductor substrate; forming a gate insulating film and a floating gate electrode by etching the first insulating film and the floating gate electrode material, respectively, and forming a groove for an element isolation region by etching the semiconductor substrate; and forming an element region and the element isolation region by burying a second insulating film in the groove and planarizing the second insulating film.

Abstract: An embodiment of the invention provides a semiconductor fabrication method. The method comprises forming an isolation region between a first and a second region in a substrate, forming a recess in the substrate surface, and lining the recess with a uniform oxide. Embodiments further include doping a channel region under the bottom recess surface in the first and second regions and depositing a gate electrode material in the recess. Preferred embodiments include forming source/drain regions adjacent the channel region in the first and second regions, preferably after the step of depositing the gate electrode material. Another embodiment of the invention provides a semiconductor device comprising a recess in a surface of the first and second active regions and in the isolation region, and a dielectric layer having a uniform thickness lining the recess.

Abstract: A flash memory device includes a source region formed in an active region of a semiconductor substrate; a recessed region formed in the active region on either side of the source region, the recessed region including a recess surface having sidewalls; floating gates formed at the sidewalls of the recess surface by interposing a tunnel insulating film; a source line formed on the source region across the active region; and control gate electrodes formed at sidewalls of the source line across a portion of the active region where the floating gates are formed. The floating gates and the control gate electrodes are formed by anisotropically etching a conformal conductive film to have a spacer structure. Cell transistor size can be reduced by forming a deposition gate structure at both sides of the source line, and short channel effects can be minimized by forming the channel between the sidewalls of a recess surface.

Abstract: A method for fabricating a semiconductor memory apparatus is provided to minimize failure of the semiconductor memory apparatus and to secure a processing margin. The method also provides for minimizing the deterioration of an operating speed and the operational stability, and minimizing the increase of resistance occurring as a result of a reduced processing margin when forming a gate pattern in a peripheral region of the semiconductor memory apparatus. The method includes forming a connection pad in a peripheral region while forming a buried word line in a cell region, and forming a gate pattern in the peripheral region while forming a bit line in the cell region.

Abstract: A method for manufacturing a non-volatile memory is provided. The method comprises steps of providing a substrate. Thereafter, a plurality of first doped regions are formed in the substrate and then a plurality of trenches are formed in a portion of the first doped regions. A plurality of second doped regions are formed in a portion of the substrate under the bottoms of the trenches respectively. Then, a charge storage layer is formed conformal to a surface of the substrate and a conductive layer is formed over the substrate, wherein the conductive layer covers the charge storage layer and fills in the trenches.

Abstract: A method includes defining active regions on a substrate, forming a dummy gate stack material over exposed portions of the active regions of the substrate and non-active regions of the substrate, removing portions of the dummy gate stack material to expose portions of the active regions and non-active regions of the substrate and define dummy gate stacks, forming a gap-fill dielectric material over the exposed portions of the substrate and the source and drain regions, removing portions of the gap-fill dielectric material to expose the dummy gate stacks, removing the dummy gate stacks to form dummy gate trenches, forming dividers within the dummy gate trenches, depositing gate stack material inside the dummy gate trenches, over the dividers, and the gap-fill dielectric material, and removing portions of the gate stack material to define gate stacks.

Abstract: Methods of manufacturing NOR-type flash memory device include forming a tunnel oxide layer on a substrate, forming a first conductive layer on the tunnel oxide layer, forming first mask patterns parallel to one another on the first conductive layer in a y direction of the substrate, and selectively removing the first conductive layer and the tunnel oxide layer using the first mask patterns as an etch mask. Thus, first conductive patterns and tunnel oxide patterns are formed, and first trenches are formed to expose the surface of the substrate between the first conductive patterns and the tunnel oxide patterns. A photoresist pattern is formed to open at least one of the first trenches, and impurity ions are implanted using the photoresist pattern as a first ion implantation mask to form an impurity region extending in a y direction of the substrate. The photoresist pattern is removed.

Abstract: A non-volatile memory device includes a channel that extends from a substrate in a vertical direction and includes a first portion including an impurity doped region and a second portion disposed under the first portion; and a plurality of memory cells and a selection transistor that are stacked over the substrate along the channel, where the impurity doped region includes a second impurity doped region that forms a side surface and an upper surface of the first portion and a first impurity doped region that covers the second impurity doped region, and a bandgap energy of the second impurity doped region is lower than a bandgap energy of the first impurity doped region.

Abstract: A semiconductor device and a method for forming the same are disclosed. The semiconductor device includes vertical pillars formed by etching a semiconductor substrate and junction regions which are located among the neighboring vertical pillars and spaced apart from one another in a zigzag pattern. As a result, the semiconductor device easily guarantees an electrical passage between the semiconductor substrate and the vertical pillars, such that it substantially prevents the floating phenomenon from being generated, resulting in the prevention of deterioration of the semiconductor device.

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 semiconductor-device fabrication method includes forming a second semiconductor region of a second conductivity on a surface layer of a first semiconductor region of a first conductivity, the second semiconductor region having an impurity concentration higher than the first semiconductor region; forming a trench penetrating the second semiconductor region, to the first semiconductor region; embedding a first electrode inside the trench via an insulating film, at a height lower than a surface of the second semiconductor region; forming an interlayer insulating film inside the trench, covering the first electrode; leaving the interlayer insulating film on only a surface of the first electrode; removing the second semiconductor region such that the surface thereof is positioned lower than an interface between the first electrode and the interlayer insulating film; and forming a second electrode contacting the second semiconductor region and adjacent to the first electrode via the insulating film in the trench.

Abstract: This invention discloses a semiconductor power device disposed on a semiconductor substrate includes a plurality of deep trenches with an epitaxial layer filling said deep trenches and a simultaneously grown top epitaxial layer covering areas above a top surface of said deep trenches over the semiconductor substrate. A plurality of trench MOSFET cells disposed in said top epitaxial layer with the top epitaxial layer functioning as the body region and the semiconductor substrate acting as the drain region whereby a super-junction effect is achieved through charge balance between the epitaxial layer in the deep trenches and regions in the semiconductor substrate laterally adjacent to the deep trenches. Each of the trench MOSFET cells further includes a trench gate and a gate-shielding dopant region disposed below and substantially aligned with each of the trench gates for each of the trench MOSFET cells for shielding the trench gate during a voltage breakdown.

Abstract: Process for manufacturing a semiconductor power device, wherein a trench is formed in a semiconductor body having a first conductivity type; the trench is annealed for shaping purpose; and the trench is filled with semiconductor material via epitaxial growth so as to obtain a first column having a second conductivity type. The epitaxial growth is performed by supplying a gas containing silicon and a gas containing dopant ions of the second conductivity type in presence of a halogenide gas and occurs with uniform distribution of the dopant ions. The flow of the gas containing dopant ions is varied according to a linear ramp during the epitaxial growth; in particular, in the case of selective growth of the semiconductor material in the presence of a hard mask, the flow decreases; in the case of non-selective growth, in the absence of hard mask, the flow increases.

Abstract: Exemplary power semiconductor devices with features providing increased breakdown voltage and other benefits are disclosed.

Abstract: A three dimensional (3-D) non-volatile memory device includes a pipe gate including a first pipe gate, a second pipe gate formed on the first pipe gate, and a first interlayer insulating layer interposed between the first pipe gate and the second pipe gate, word lines alternately stacked with second interlayer insulating layers on the pipe gate, a pipe channel buried within the pipe gate, and memory cell channels coupled to the pipe channel and arranged to pass through the word lines and the second interlayer insulating layers.

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.

Abstract: A semiconductor device including a first doped region of a first conductivity type, a second doped region of a second conductivity type, a gate, and a dielectric layer is provided. The first doped region is located in a substrate and has a trench. The second doped region is located at the bottom of the trench to separate the first doped region into a source doped region and a drain doped region. A channel region is located between the source doped region and the drain doped region. The gate is located in the trench. The dielectric layer covers the sidewall and the bottom of the trench and separates the gate and the substrate.

Abstract: Fabricating a semiconductor device includes forming a hard mask on the substrate having a top substrate surface; forming a gate trench in the substrate, through the hard mask; depositing gate material in the gate trench; removing the hard mask to leave a gate structure; implanting a body region; implanting a source region; forming a source body contact trench having a trench wall and a trench bottom; and disposing an anti-punch through implant along at least a section of the trench wall but not along the trench bottom.

Abstract: A fabrication method of a self-aligned power semiconductor structure is provided. Firstly, a trenched polysilicon gate is formed in a silicon substrate. Then, a self-aligned polysilicon extending structure is formed on the trenched polysilicon gate. A width of the self-aligned polysilicon extending structure is smaller than that of the trenched polysilicon gate. Thereafter, the self-aligned polysilicon extending structure is oxidized to form a silicon oxide protruding structure on the trenched polysilicon gate. Then, a first spacer is formed on a sidewall of the silicon oxide protruding structure to define a source contact window.

Abstract: An integrated circuit with a memory cell is disclosed. The integrated circuit with a memory cell includes: a word line disposed in a word line trench of a substrate; a bit line disposed below the word line in a bit line trench and extending orthogonal to the word line; and, a separating layer disposed above the bit line in the bit line trench that separates the word line from the bit line; wherein an etching rate of the separating layer approaches that of the substrate.

Abstract: A field effect transistor includes a plurality of trenches extending into a semiconductor region of a first conductivity type. The plurality of trenches includes a plurality of gated trenches and a plurality of non-gated trenches. A body region of a second conductivity extends in the semiconductor region between adjacent trenches. A dielectric material fills a bottom portion of each of the gated and non-gated trenches. A gate electrode is disposed in each gated trench. A conductive material of the second conductivity type is disposed in each non-gated trench such that the conductive material and contacts corresponding body regions along sidewalls of the non-gated trench.

Abstract: A FET is formed as follows. A trench is formed in a silicon region. A shield electrode is formed in a bottom portion of the trench. The shield electrode is insulated from adjacent silicon region by a shield dielectric. A silicon nitride layer is formed over a surface of the silicon region adjacent the trench, along the trench sidewalls, and over the shield electrode and shield dielectric. A layer of LTO is formed over the silicon nitride layer such that those portions of the LTO layer extending over the surface of the silicon region adjacent the trench are thicker than the portion of the LTO layer extending over the shield electrode. The LTO layer is uniformly etched back such that a portion of the silicon nitride layer becomes exposed while portions of the silicon nitride layer remain covered.