WO2003046997A1 - Trench mosfet device with improved on-resistance - Google Patents

Trench mosfet device with improved on-resistance Download PDF

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Publication number
WO2003046997A1
WO2003046997A1 PCT/US2002/037265 US0237265W WO03046997A1 WO 2003046997 A1 WO2003046997 A1 WO 2003046997A1 US 0237265 W US0237265 W US 0237265W WO 03046997 A1 WO03046997 A1 WO 03046997A1
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WIPO (PCT)
Prior art keywords
trench
region
substrate
epitaxial layer
mosfet device
Prior art date
Application number
PCT/US2002/037265
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French (fr)
Inventor
Fwu-Iuan Hshieh
Koon Chong So
John E. Amato
Yan Man Tsui
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General Semiconductor, Inc.
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Publication date
Application filed by General Semiconductor, Inc. filed Critical General Semiconductor, Inc.
Priority to KR1020047007618A priority Critical patent/KR100957584B1/en
Priority to JP2003548314A priority patent/JP2005510881A/en
Priority to AU2002348308A priority patent/AU2002348308A1/en
Priority to EP02782334A priority patent/EP1454360A4/en
Publication of WO2003046997A1 publication Critical patent/WO2003046997A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
    • H01L29/76—Unipolar devices, e.g. field effect transistors
    • H01L29/772—Field effect transistors
    • H01L29/78—Field effect transistors with field effect produced by an insulated gate
    • H01L29/7801—DMOS transistors, i.e. MISFETs with a channel accommodating body or base region adjoining a drain drift region
    • H01L29/7802—Vertical DMOS transistors, i.e. VDMOS transistors
    • H01L29/7813—Vertical DMOS transistors, i.e. VDMOS transistors with trench gate electrode, e.g. UMOS transistors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/0445—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising crystalline silicon carbide
    • H01L21/0455—Making n or p doped regions or layers, e.g. using diffusion
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
    • H01L29/06—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions
    • H01L29/08—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions with semiconductor regions connected to an electrode carrying current to be rectified, amplified or switched and such electrode being part of a semiconductor device which comprises three or more electrodes
    • H01L29/0843—Source or drain regions of field-effect devices
    • H01L29/0847—Source or drain regions of field-effect devices of field-effect transistors with insulated gate
    • H01L29/0852—Source or drain regions of field-effect devices of field-effect transistors with insulated gate of DMOS transistors
    • H01L29/0873—Drain regions
    • H01L29/0878—Impurity concentration or distribution
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007—Multistep manufacturing processes
    • H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
    • H01L29/66409—Unipolar field-effect transistors
    • H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
    • H01L29/66674—DMOS transistors, i.e. MISFETs with a channel accommodating body or base region adjoining a drain drift region
    • H01L29/66712—Vertical DMOS transistors, i.e. VDMOS transistors
    • H01L29/66734—Vertical DMOS transistors, i.e. VDMOS transistors with a step of recessing the gate electrode, e.g. to form a trench gate electrode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
    • H01L29/76—Unipolar devices, e.g. field effect transistors
    • H01L29/772—Field effect transistors
    • H01L29/78—Field effect transistors with field effect produced by an insulated gate
    • H01L29/7801—DMOS transistors, i.e. MISFETs with a channel accommodating body or base region adjoining a drain drift region
    • H01L29/7802—Vertical DMOS transistors, i.e. VDMOS transistors
    • H01L29/7812—Vertical DMOS transistors, i.e. VDMOS transistors with a substrate comprising an insulating layer, e.g. SOI-VDMOS transistors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/11—Device type
    • H01L2924/13—Discrete devices, e.g. 3 terminal devices
    • H01L2924/1304—Transistor
    • H01L2924/1306—Field-effect transistor [FET]
    • H01L2924/13091—Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]

Definitions

  • a trench MOSFET metal-oxide-semiconductor field-effect transistor
  • a trench MOSFET metal-oxide-semiconductor field-effect transistor
  • the trench which is lined with a thin insulator layer such as an oxide layer and filled with a conductor such as polysilicon (i.e., polycrystalline silicon), allows less constricted current flow and thereby provides lower values of specific on-resistance.
  • Examples of trench MOSFET transistors are disclosed, for example, in U.S. Patent Nos. 5,072,266, 5,541,425, and 5,866,931, the disclosures of which are hereby incorporated by reference.
  • Figure 1 illustrates half of a hexagonally shaped trench MOSFET structure 21 disclosed in U.S. Patent No. 5,072,266.
  • the structure includes an n+ substrate 23, upon which is grown a lightly doped n epitaxial layer 25 of a predetermined depth d ep i.
  • p body region 27 (p, p+) is provided within the epitaxial layer 25 .
  • the p body region 27 is substantially planar (except in a central region) and typically lays a distance d m j n below the top surface of the epitaxial layer.
  • Another layer 28 (n+) overlying most of the p body region 27 serves as source for the device.
  • a series of hexagonally shaped trenches 29 are provided in the epitaxial layer, opening toward the top and having a predetermined depth d t -.
  • the trenches 29 are typically lined with oxide and filled with conductive polysilicon, forming the gate for the MOSFET device.
  • the trenches 29 define cell regions 31 that are also hexagonally shaped in horizontal cross-section.
  • the p body region 27 rises to the top surface of the epitaxial layer and forms an exposed pattern 33 in a horizontal cross section at the top surface of the cell region 31.
  • a typical MOSFET device includes numerous individual MOSFET cells that are fabricated in parallel within a single chip (i.e., a section of a semiconductor wafer). Hence, the chip shown in Fig. 1 contains numerous hexagonal-shaped cells 31 (portions of five of these cells are illustrated). Cell configurations other than hexagonal configurations are commonly used, including square-shaped configurations, hi a design like that shown in Fig.
  • the substrate region 23 acts as a common drain contact for all of the individual MOSFET cells 31.
  • all the sources for the MOSFET cells 31 are typically shorted together via a metal source contact that is disposed on top of the n+ source regions 28.
  • An insulating region, such as borophosphosilicate glass (not shown) is typically placed between the polysilicon in the trenches 29 and the metal source contact to prevent the gate regions from being shorted with the source regions. Consequently, to make gate contact, the polysilicon within the trenches 29 is typically extended into a termination region beyond the MOSFET cells 31, where a metal gate contact is provided on the polysilicon.
  • a trench MOSFET device comprises: (a) a substrate of a first conductivity type (preferably an n-type conductivity silicon substrate); (b) an epitaxial layer of the first conductivity type over the substrate, wherein the epitaxial layer has a lower majority carrier concentration than the substrate; (c) a trench extending into the epitaxial region from an upper surface of the epitaxial layer; (d) an insulating layer (preferably an oxide layer) lining at least a portion of the trench; (e) a conductive region (preferably a doped polysilicon region) within the trench adjacent the insulating layer; (f) a doped region of the first conductivity type formed within the epitaxial layer between a bottom portion of the trench and the substrate, wherein the doped region has a majority carrier concentration that is lower than that of the substrate and higher than that of the epitaxial layer; (g) a body region of a second conductivity type (preferably p-type conductivity) formed within
  • the presence of the doped region lying between the bottom portion of the trench and the substrate serves to reduce the on-resistance of the device.
  • this region extends more than 50% of the distance from the trench bottom to the substrate, more preferably 100% of the distance from the trench bottom to the substrate.
  • a method of forming a trench MOSFET device comprises: (a) providing a substrate of a first conductivity type; (b) depositing an epitaxial layer of the first conductivity type over the substrate, the epitaxial layer having a lower majority carrier concentration than the substrate; (c) forming a body region of a second conductivity type within an upper portion of the epitaxial layer; (d) etching a trench extending into the epitaxial region from an upper surface of the epitaxial layer such that the trench extends to a greater depth from the upper surface of the epitaxial layer than does the body region; (e) forming a doped region of the first conductivity type between a bottom portion of the trench and the substrate such that the doped region has a majority carrier concentration that is lower than that of the substrate and higher than that of the epitaxial layer; (f) forming an insulating layer lining at least a portion of the trench; (g) forming a conductive region within the
  • the doped region is preferably formed by a method comprising implanting a dopant of the first conductivity type into the epitaxial region, and diffusing dopant of the first conductivity type at elevated temperature. More preferably, the doped region is formed in connection with the trench by a method comprising: (a) forming a trench mask on the epitaxial layer; (b) etching the trench through the trench mask; (c) implanting a dopant of the first conductivity type through the trench mask; and (c) diffusing the dopant at elevated temperature. Even more preferably, the diffusion step is conducted concurrently with the growth of a sacrificial oxide along walls of the trench.
  • Trench bottom implants have been previously used to address a problem arising from devices that have deep body regions which extend to greater depths than the trenches (such as the deep body regions of Fig. 1). More specifically, U.S. Patent No. 5,929,481 is directed to a trench MOSFET device having deep body regions that extend deeper than the trench. Unfortunately, these deep body regions, which are provided to avoid trench corner electrical breakdown, create the problem of a parasitic JFET at the ' trench bottom. To reduce this parasitic JFET, a doped trench bottom implant region is provided at the bottom of the trench, which extends into the surrounding drift region. The trench bottom implant region has the same doping type, but is more highly doped, than the surrounding drift region. In contrast to U.S. Patent No. 5,929,481, however, the trench MOSFET devices of the present invention are not provided with such deep body regions. Instead, the trenches of the devices of the present invention extend to a greater depth than do the body regions.
  • One advantage of the present invention is that a trench MOSFET cell is provided which has improved on-resistance.
  • Another advantage of the present invention is that a trench MOSFET cell with improved on-resistance is provided, without a substantial increase in design and process complexity.
  • Another advantage of the present invention is that a trench MOSFET cell can be provided, which has reduced resistance in the epitaxial layer between the trench bottoms and the substrate. In this way, on-resistance is reduced without thinning the epitaxial layer and compromising breakdown characteristics within the termination region.
  • Fig. 1 is a schematic cross-sectional view of a trench MOSFET device in the prior art.
  • FIG. 2 is a schematic cross-sectional view of a trench MOSFET device, according to an embodiment of the present invention.
  • Fig. 3 shows approximate plots of concentration v. distance (in arbitrary units and scale) over portions of the cross-sections defined by lines A- A' (curve a) and B-B'
  • Figs. 4A through 4C are schematic cross-sectional views illustrating a method of making a trench MOSFET device like of Fig. 2, according to an embodiment of the present invention.
  • the present invention is directed to novel trench MOSFET structures in which a region of relatively high majority carrier concentration (sometimes referred to herein as a "trench bottom implant” based on its preferred mode of formation) is provided between the trench bottom and the substrate.
  • a region of relatively high majority carrier concentration sometimes referred to herein as a "trench bottom implant” based on its preferred mode of formation
  • One advantage associated with such a trench MOSFET structure is improved on-resistance.
  • FIG. 2 illustrates a trench MOSFET in accordance with an embodiment of the present invention.
  • an epitaxial layer 201 is provided on an epitaxial layer 201 .
  • the N+ substrate 200 in this specific example is a silicon substrate having a thickness ranging, for example, from 10 to 25 mils and a net doping concentration ranging, for example, from IxlO 19 to lxlO 20 cm "3 .
  • N- regions 202 are found in the lower portion of the epitaxial layer 201. ha this example, these regions have a thickness ranging from, for example, 2 to 5 microns and a net doping concentration ranging, for example, from 4x10 15 to 8x10 16 cm "3 .
  • P-body regions 204 are found in the upper portion of the epitaxial layer 201.
  • these P-body regions 204 range, for example, from 1 to 2 microns in thickness and have a net doping concentration ranging, for example, from 1 xlO 17 to 1 xl0 18 cm '3 .
  • Trenches formed within the epitaxial layer are lined with an insulator 210, such as oxide, and are filled with a conductor 211, such as doped polysilicon, providing the gate electrode function of the device.
  • the trenches typically have a depth of 1.5 to 2.5 microns. Where silicon oxide (typically as silicon dioxide) is used as the insulator 210, it can be for example, 500 to 700 Angstroms thick. Where polysilicon is used as the conductor 211, it can have a resistivity of, for example, 1 to 15ohm/sq.
  • the regions between the trenches are frequently referred to as “mesas" or “trench mesas", based on their shapes. These regions are commonly square or hexagonal in plan view.
  • N regions 206 are provided between the trench bottoms and the N+ substrate.
  • N regions 206 have a net doping concentration ranging, for example, from 1 xlO 18 to 5xl0 19 cm “3 .
  • These regions 206 preferably extend the entire distance from the trench bottoms to the N+ substrate 200 as shown, but can also partially bridge the distance if desired. Typically, these regions range from 1 to 6 microns in depth.
  • the trench MOSFET device of Figure 2 also contains N+ source regions 212, which extend, in the embodiment illustrated, to a depth of 0.3 to 0.5 micron from the epitaxial layer surface and have net doping concentrations ranging, for example, from 5 xlO 19 to 5xl0 20 cm "3 .
  • the left-hand portion of curve a corresponds to N region 206, while the right-hand portion corresponds to the N+ substrate 200.
  • the approximate doping profile found along a parallel portion of line B-B' within Fig. 2 is illustrated in curve b of Fig. 3.
  • the left-hand portion of curve b corresponds to the N- epitaxial region 202, while the right-hand portion corresponds to the N+ substrate 200.
  • FIG. 2 A method for manufacturing a trench MOSFET like that shown in Fig. 2 will now be described in connection with Figs. 4A to Fig. 4C, in accordance with one embodiment of the present invention.
  • an N doped epitaxial layer 201 is initially grown on an N+ doped substrate 200.
  • the N+ doped substrate 200 for example, can be from 10 to
  • the epitaxial layer 201 can have a net n-type doping concentration of 4xl0 15 to 8xl0 16 cm “3 and can range from 3 to 10 microns in thickness.
  • a P-type region 204 is then formed in the epitaxial layer 201 by implantation and diffusion.
  • the epitaxial layer 201 may be implanted with boron followed by diffusion at elevated temperature to produce a
  • P-type region 204 which can be 1 to 2 microns thick and have a net p-type doping concentration ranging, for example, from 1 xlO 17 to 1 xlO 18 cm "3 .
  • N- portion 202 of the epitaxial layer 201 remains, which can be 2 to 5 microns thick.
  • N- portion 202 has the n-type doping concentration noted above for epitaxial layer 201.
  • a mask oxide layer 203 is then deposited, for example, by chemical vapor deposition, and etched by reactive ion etch after being provided with a patterned trench mask (not shown). The resulting structure is shown in Fig. 4A.
  • Trenches are then etched through apertures in the patterned mask oxide layer
  • Trench depths in this example are about 1.5 to 2.5 microns.
  • Discrete P-body regions 204 are established as a result of this trench-forming step.
  • an n-type dopant preferably phosphorous
  • phosphorous is implanted at 80 to 100 keV with a dosage of 5 xlO 15 to 1 xlO 17 cm "3 .
  • the resulting structure is shown in Fig. 4B.
  • the dashed lines found below the trench bottom illustrate the presence of phosphorous within the structure.
  • the implanted n-type dopant e.g., phosphorous
  • dopant diffusion is carried out concurrently with the formation of a sacrificial oxide layer.
  • a sacrificial oxide layer is grown within the trench at this point, typically by dry oxidation at 900 to 1150 °C for 20 to 60 minutes.
  • this elevated temperature step drives the implanted n-type dopant into the N-type region 202 of the epitaxial layer, forming N regions 206.
  • the resulting structure is illustrated in Fig. 4C.
  • the trench MOSFET is completed to form a structure like that shown in Fig. 2.
  • the sacrificial oxide regions 205 seen in Fig. 4C are removed from the trenches, preferably by wet etch.
  • An oxide layer which is preferably 500 to 700 Angstroms thick, is then grown over the trench bottom, for example, by dry oxidation at 900 to 1100 °C for 20 to 60 minutes. Portions of this oxide layer ultimately form the gate oxide regions 210 for the finished device.
  • the surface of the structure is then covered, and the trenches are filled, with a polysilicon layer, preferably using CVD.
  • the polysilicon is typically doped N-type to reduce its resistivity. N-type doping can be carried out, for example, during CVD with phosphorous chloride or by implantation with arsenic or phosphorous.
  • the polysilicon layer is then etched, for example, by reactive ion etching.
  • the polysilicon layer within the trench segments is commonly slightly over-etched due to etching uniformity concerns, and the thus-formed polysilicon gate regions 211 typically have top surfaces that are 0.1 to 0.2 microns below the adjacent surface of the epitaxial layer 204.
  • n+ source regions 212 which preferably extend to a depth of 0.3 to 0.5 microns and from the epitaxial layer surface and have net doping concentrations ranging, for example, from 5x10 to 5x10 cm ' , are formed in upper portions of the epitaxial layer through the masking layer via an implantation and diffusion process. Implantation is preferably conducted through an implant oxide to avoid implant-channeling effects, implant damage, and heavy metal contamination during formation of the source regions.
  • a BPSG (borophosphosilicate glass) layer is then formed over the entire structure, for example, by PECVD.
  • the stmcture is then etched, typically by reactive ion etching, to remove the BPSG and oxide layers over selected portions of the structure, forming BPSG regions 216.
  • the patterned photoresist layer is then removed, and a metal contact layer is deposited, forming source contact 218. Gate and drain contacts (not shown) are also typically provided.
  • the resulting stmcture is like that of Fig. 2.

Abstract

A trench MOSFET device comprises: a substrate (200) of a first conductivity type; an epitaxial layer (202) of the first conductivity type; wherein the epitaxial layer has a lower impurity concentration than the substrate; a trench extending into the epitaxial layer; an insulated conductive region (211) within the trench; a doped region (206) of the first conductivity type formed within the epitaxial layer between a bottom portion of the trench and the substrate, wherein the doped region has an impurity concentration that is lower than that of the substrate and higher than that of the epitaxial layer; a body region (204) of a second conductivity type formed within an upper portion of the epitaxial layer and adjacent trench; wherein the body region extends to a lesser depth from the upper surface of the epitaxial layer than does the trench; a source region (212) within the body region.

Description

TRENCH MOSFET DEVICE WITH IMPROVED ON-RESISTANCE
BACKGROUND OF THE INVENTION
[0001] The present invention relates to trench MOSFET devices, and more particularly to trench MOSFET devices with improved on-resistance. [0002] A trench MOSFET (metal-oxide-semiconductor field-effect transistor) is a transistor in which the channel is formed vertically and the gate is formed in a trench extending between the source and drain. The trench, which is lined with a thin insulator layer such as an oxide layer and filled with a conductor such as polysilicon (i.e., polycrystalline silicon), allows less constricted current flow and thereby provides lower values of specific on-resistance. Examples of trench MOSFET transistors are disclosed, for example, in U.S. Patent Nos. 5,072,266, 5,541,425, and 5,866,931, the disclosures of which are hereby incorporated by reference.
[0003] As a specific example, Figure 1 illustrates half of a hexagonally shaped trench MOSFET structure 21 disclosed in U.S. Patent No. 5,072,266. The structure includes an n+ substrate 23, upon which is grown a lightly doped n epitaxial layer 25 of a predetermined depth depi. Within the epitaxial layer 25, p body region 27 (p, p+) is provided. In the design shown, the p body region 27 is substantially planar (except in a central region) and typically lays a distance dmjn below the top surface of the epitaxial layer. Another layer 28 (n+) overlying most of the p body region 27 serves as source for the device. A series of hexagonally shaped trenches 29 are provided in the epitaxial layer, opening toward the top and having a predetermined depth dt-. The trenches 29 are typically lined with oxide and filled with conductive polysilicon, forming the gate for the MOSFET device. The trenches 29 define cell regions 31 that are also hexagonally shaped in horizontal cross-section. Within the cell region 31, the p body region 27 rises to the top surface of the epitaxial layer and forms an exposed pattern 33 in a horizontal cross section at the top surface of the cell region 31. In the specific design illustrated, the p+ central portion of the p body region 27 extends to a depth dmax below the surface of the epitaxial layer that is greater than the trench depth dπ- for the transistor cell so that breakdown voltage is away from the trench surface and into the bulk of the semiconductor material. [0004] A typical MOSFET device includes numerous individual MOSFET cells that are fabricated in parallel within a single chip (i.e., a section of a semiconductor wafer). Hence, the chip shown in Fig. 1 contains numerous hexagonal-shaped cells 31 (portions of five of these cells are illustrated). Cell configurations other than hexagonal configurations are commonly used, including square-shaped configurations, hi a design like that shown in Fig. 1, the substrate region 23 acts as a common drain contact for all of the individual MOSFET cells 31. Although not illustrated, all the sources for the MOSFET cells 31 are typically shorted together via a metal source contact that is disposed on top of the n+ source regions 28. An insulating region, such as borophosphosilicate glass (not shown) is typically placed between the polysilicon in the trenches 29 and the metal source contact to prevent the gate regions from being shorted with the source regions. Consequently, to make gate contact, the polysilicon within the trenches 29 is typically extended into a termination region beyond the MOSFET cells 31, where a metal gate contact is provided on the polysilicon. Since the polysilicon gate regions are interconnected with one another via the trenches, this arrangement provides a single gate contact for all the gate regions of the device. As a result of this scheme, even though the chip contains a matrix of individual transistor cells 31, these cells 31 behave as a single large transistor.
[0005] Demand persists for trench MOSFET devices having ever-lower on- resistance. One way to decrease on-resistance is to decrease the thickness of the epitaxial layer. As a result, the region of the epitaxial layer lying between the body region and the substrate (see numeral 25 in Fig. 1) is reduced in thickness. Since this region is of relatively high resistivity, the on-resistance of the device is reduced. However, as is known in the art, the risk of breakdown increases as the epitaxial layer becomes thinner, particularly in the termination region, which is more vulnerable to breakdown. SUMMARY OF THE INVENTION
[0006] According to an embodiment of the invention, a trench MOSFET device is provided. The device comprises: (a) a substrate of a first conductivity type (preferably an n-type conductivity silicon substrate); (b) an epitaxial layer of the first conductivity type over the substrate, wherein the epitaxial layer has a lower majority carrier concentration than the substrate; (c) a trench extending into the epitaxial region from an upper surface of the epitaxial layer; (d) an insulating layer (preferably an oxide layer) lining at least a portion of the trench; (e) a conductive region (preferably a doped polysilicon region) within the trench adjacent the insulating layer; (f) a doped region of the first conductivity type formed within the epitaxial layer between a bottom portion of the trench and the substrate, wherein the doped region has a majority carrier concentration that is lower than that of the substrate and higher than that of the epitaxial layer; (g) a body region of a second conductivity type (preferably p-type conductivity) formed within an upper portion of the epitaxial layer and adjacent the trench, wherein the body region extends to a lesser depth from the upper surface of the epitaxial layer than does the trench; and (h) a source region of the first conductivity type formed within an upper portion of the body region and adjacent the trench.
[0007] The presence of the doped region lying between the bottom portion of the trench and the substrate (sometimes referred to herein as a "trench bottom implant" based on its preferred mode of formation) serves to reduce the on-resistance of the device. Preferably this region extends more than 50% of the distance from the trench bottom to the substrate, more preferably 100% of the distance from the trench bottom to the substrate.
[0008] According to another embodiment of the invention, a method of forming a trench MOSFET device is provided. The method comprises: (a) providing a substrate of a first conductivity type; (b) depositing an epitaxial layer of the first conductivity type over the substrate, the epitaxial layer having a lower majority carrier concentration than the substrate; (c) forming a body region of a second conductivity type within an upper portion of the epitaxial layer; (d) etching a trench extending into the epitaxial region from an upper surface of the epitaxial layer such that the trench extends to a greater depth from the upper surface of the epitaxial layer than does the body region; (e) forming a doped region of the first conductivity type between a bottom portion of the trench and the substrate such that the doped region has a majority carrier concentration that is lower than that of the substrate and higher than that of the epitaxial layer; (f) forming an insulating layer lining at least a portion of the trench; (g) forming a conductive region within the trench adjacent the insulating layer; (h) forming a source region of the first conductivity type within an upper portion of the body region and adjacent the trench. [0009] The doped region is preferably formed by a method comprising implanting a dopant of the first conductivity type into the epitaxial region, and diffusing dopant of the first conductivity type at elevated temperature. More preferably, the doped region is formed in connection with the trench by a method comprising: (a) forming a trench mask on the epitaxial layer; (b) etching the trench through the trench mask; (c) implanting a dopant of the first conductivity type through the trench mask; and (c) diffusing the dopant at elevated temperature. Even more preferably, the diffusion step is conducted concurrently with the growth of a sacrificial oxide along walls of the trench. [0010] Trench bottom implants have been previously used to address a problem arising from devices that have deep body regions which extend to greater depths than the trenches (such as the deep body regions of Fig. 1). More specifically, U.S. Patent No. 5,929,481 is directed to a trench MOSFET device having deep body regions that extend deeper than the trench. Unfortunately, these deep body regions, which are provided to avoid trench corner electrical breakdown, create the problem of a parasitic JFET at the ' trench bottom. To reduce this parasitic JFET, a doped trench bottom implant region is provided at the bottom of the trench, which extends into the surrounding drift region. The trench bottom implant region has the same doping type, but is more highly doped, than the surrounding drift region. In contrast to U.S. Patent No. 5,929,481, however, the trench MOSFET devices of the present invention are not provided with such deep body regions. Instead, the trenches of the devices of the present invention extend to a greater depth than do the body regions.
[0011] One advantage of the present invention is that a trench MOSFET cell is provided which has improved on-resistance. [0012] Another advantage of the present invention is that a trench MOSFET cell with improved on-resistance is provided, without a substantial increase in design and process complexity.
[0013] Another advantage of the present invention is that a trench MOSFET cell can be provided, which has reduced resistance in the epitaxial layer between the trench bottoms and the substrate. In this way, on-resistance is reduced without thinning the epitaxial layer and compromising breakdown characteristics within the termination region.
[0014] The above and other embodiments and advantages of the present invention will become immediately apparent to those of ordinary skill in the art upon review of the
Detailed Description and Claims to follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Fig. 1 is a schematic cross-sectional view of a trench MOSFET device in the prior art.
[0016] Fig. 2 is a schematic cross-sectional view of a trench MOSFET device, according to an embodiment of the present invention.
[0017] Fig. 3 shows approximate plots of concentration v. distance (in arbitrary units and scale) over portions of the cross-sections defined by lines A- A' (curve a) and B-B'
(curve b) of Fig. 2.
[0018] Figs. 4A through 4C are schematic cross-sectional views illustrating a method of making a trench MOSFET device like of Fig. 2, according to an embodiment of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE
INVENTION
[0019] The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the present invention are shown. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein.
[0020] The present invention is directed to novel trench MOSFET structures in which a region of relatively high majority carrier concentration (sometimes referred to herein as a "trench bottom implant" based on its preferred mode of formation) is provided between the trench bottom and the substrate. One advantage associated with such a trench MOSFET structure is improved on-resistance.
[0021] Fig. 2 illustrates a trench MOSFET in accordance with an embodiment of the present invention. In the trench MOSFET shown, an epitaxial layer 201 is provided on an
N+ substrate 200.
[0022] The N+ substrate 200 in this specific example is a silicon substrate having a thickness ranging, for example, from 10 to 25 mils and a net doping concentration ranging, for example, from IxlO19 to lxlO20 cm"3.
[0023] N- regions 202 are found in the lower portion of the epitaxial layer 201. ha this example, these regions have a thickness ranging from, for example, 2 to 5 microns and a net doping concentration ranging, for example, from 4x1015 to 8x1016 cm"3.
[0024] P-body regions 204 are found in the upper portion of the epitaxial layer 201.
In the example shown, these P-body regions 204 range, for example, from 1 to 2 microns in thickness and have a net doping concentration ranging, for example, from 1 xlO17 to 1 xl018 cm'3.
[0025] Trenches formed within the epitaxial layer are lined with an insulator 210, such as oxide, and are filled with a conductor 211, such as doped polysilicon, providing the gate electrode function of the device. The trenches typically have a depth of 1.5 to 2.5 microns. Where silicon oxide (typically as silicon dioxide) is used as the insulator 210, it can be for example, 500 to 700 Angstroms thick. Where polysilicon is used as the conductor 211, it can have a resistivity of, for example, 1 to 15ohm/sq. The regions between the trenches are frequently referred to as "mesas" or "trench mesas", based on their shapes. These regions are commonly square or hexagonal in plan view.
[0026] In accordance with the present invention, N regions 206 (also referred to herein as "trench bottom implants") are provided between the trench bottoms and the N+ substrate. N regions 206 have a net doping concentration ranging, for example, from 1 xlO18 to 5xl019 cm"3. These regions 206 preferably extend the entire distance from the trench bottoms to the N+ substrate 200 as shown, but can also partially bridge the distance if desired. Typically, these regions range from 1 to 6 microns in depth. [0027] The trench MOSFET device of Figure 2 also contains N+ source regions 212, which extend, in the embodiment illustrated, to a depth of 0.3 to 0.5 micron from the epitaxial layer surface and have net doping concentrations ranging, for example, from 5 xlO19 to 5xl020 cm"3.
[0028] Electrical contact is made with the N+ source regions 212 via metal source contact 218. Insulating regions such as BPSG (borophosphosilicate glass) regions 216 prevent the polysilicon regions 211 associated with the gate electrodes from being shorted to the N+ source regions 212 through the source contact 218. A separate metal gate contact (not shown) is typically connected to the gate runner portion of the polysilicon 211 located outside of the region of the trench MOSFET cells. A metal drain contact (not shown) is also typically provided adjacent the N+ substrate 200. [0029] Illustrated in curve a of Fig. 3 is the approximate doping profile found along the portion of line A- A' of Fig. 2 that begins at the trench bottom and extends into the substrate 200. The left-hand portion of curve a corresponds to N region 206, while the right-hand portion corresponds to the N+ substrate 200. For comparison, the approximate doping profile found along a parallel portion of line B-B' within Fig. 2 is illustrated in curve b of Fig. 3. The left-hand portion of curve b corresponds to the N- epitaxial region 202, while the right-hand portion corresponds to the N+ substrate 200. [0030] Although not wishing to be bound by theory, it is believed that, upon creation of a potential difference between the p-body regions 204 and the polysilicon regions 211 of the gate, charges are capacitively induced within the p-body body regions 204 adjacent to the gate oxide layer 210, resulting in the formation of channels within the p-body regions 204. When another potential difference is provided between the sources 212 and the N+ substrate 200 (corresponding to the drain), a current flows from the sources 212 to the N+ substrate 200 through the channels formed in the P-body regions 204 adjacent the gate oxide layer 210, and the trench MOSFET is said to be in the power-on state. It is further believed that the device of Fig. 2 has improved on-resistance, because the N regions 206 formed at the bases of the trenches provide paths of reduced resistance for the current flowing from the sources 212 to the drain (N+ substrate 200) while the transistor is in the power-on state.
[0031] A method for manufacturing a trench MOSFET like that shown in Fig. 2 will now be described in connection with Figs. 4A to Fig. 4C, in accordance with one embodiment of the present invention.
[0032] Turning now to Fig. 4 A, an N doped epitaxial layer 201 is initially grown on an N+ doped substrate 200. The N+ doped substrate 200, for example, can be from 10 to
25 mils and have a net doping concentration ranging, for example, from lxlO19 to lxlO20 cm"3. The epitaxial layer 201 , for example, can have a net n-type doping concentration of 4xl015 to 8xl016 cm"3 and can range from 3 to 10 microns in thickness.
[0033] Using masking as appropriate, a P-type region 204 is then formed in the epitaxial layer 201 by implantation and diffusion. For example, the epitaxial layer 201 may be implanted with boron followed by diffusion at elevated temperature to produce a
P-type region 204, which can be 1 to 2 microns thick and have a net p-type doping concentration ranging, for example, from 1 xlO17 to 1 xlO18 cm"3. After this step, an N- portion 202 of the epitaxial layer 201 remains, which can be 2 to 5 microns thick. N- portion 202 has the n-type doping concentration noted above for epitaxial layer 201.
[0034] A mask oxide layer 203 is then deposited, for example, by chemical vapor deposition, and etched by reactive ion etch after being provided with a patterned trench mask (not shown). The resulting structure is shown in Fig. 4A.
[0035] Trenches are then etched through apertures in the patterned mask oxide layer
203, typically by reactive ion etching. Trench depths in this example are about 1.5 to 2.5 microns. Discrete P-body regions 204 are established as a result of this trench-forming step.
[0036] At this point, an n-type dopant, preferably phosphorous, is implanted into the structure using the trench mask as an implantation mask. In this example, phosphorous is implanted at 80 to 100 keV with a dosage of 5 xlO15 to 1 xlO17 cm"3. The resulting structure is shown in Fig. 4B. The dashed lines found below the trench bottom illustrate the presence of phosphorous within the structure.
[0037] Although the implanted n-type dopant (e.g., phosphorous) can be diffused into the structure at this point by simply heating the structure, according to a preferred embodiment, dopant diffusion is carried out concurrently with the formation of a sacrificial oxide layer. Specifically, a sacrificial oxide layer is grown within the trench at this point, typically by dry oxidation at 900 to 1150 °C for 20 to 60 minutes. As a result, in addition to forming sacrificial oxide regions 205, this elevated temperature step drives the implanted n-type dopant into the N-type region 202 of the epitaxial layer, forming N regions 206. The resulting structure is illustrated in Fig. 4C.
[0038] Subsequently, the trench MOSFET is completed to form a structure like that shown in Fig. 2. For example, the sacrificial oxide regions 205 seen in Fig. 4C are removed from the trenches, preferably by wet etch. An oxide layer, which is preferably 500 to 700 Angstroms thick, is then grown over the trench bottom, for example, by dry oxidation at 900 to 1100 °C for 20 to 60 minutes. Portions of this oxide layer ultimately form the gate oxide regions 210 for the finished device.
[0039] The surface of the structure is then covered, and the trenches are filled, with a polysilicon layer, preferably using CVD. The polysilicon is typically doped N-type to reduce its resistivity. N-type doping can be carried out, for example, during CVD with phosphorous chloride or by implantation with arsenic or phosphorous. The polysilicon layer is then etched, for example, by reactive ion etching. The polysilicon layer within the trench segments is commonly slightly over-etched due to etching uniformity concerns, and the thus-formed polysilicon gate regions 211 typically have top surfaces that are 0.1 to 0.2 microns below the adjacent surface of the epitaxial layer 204. [0040] A patterned masking layer is then provided and n+ source regions 212, which preferably extend to a depth of 0.3 to 0.5 microns and from the epitaxial layer surface and have net doping concentrations ranging, for example, from 5x10 to 5x10 cm' , are formed in upper portions of the epitaxial layer through the masking layer via an implantation and diffusion process. Implantation is preferably conducted through an implant oxide to avoid implant-channeling effects, implant damage, and heavy metal contamination during formation of the source regions.
[0041] A BPSG (borophosphosilicate glass) layer is then formed over the entire structure, for example, by PECVD. After providing the structure with a patterned photoresist layer, the stmcture is then etched, typically by reactive ion etching, to remove the BPSG and oxide layers over selected portions of the structure, forming BPSG regions 216. The patterned photoresist layer is then removed, and a metal contact layer is deposited, forming source contact 218. Gate and drain contacts (not shown) are also typically provided. The resulting stmcture is like that of Fig. 2. [0042] Although various embodiments are specifically illustrated and described herein, it will be appreciated that modifications and variations of the present invention are covered by the above teachings and are within the purview of the appended claims without departing from the spirit and intended scope of the invention. As one example, the method of the present invention may be used to form a structure in which the conductivities of the various semiconductor regions are reversed from those described herein.

Claims

CLAIMS:
1. A trench MOSFET device comprising: a substrate of a first conductivity type; an epitaxial layer of said first conductivity type over said substrate, said epitaxial layer having a lower majority carrier concentration than said substrate; a trench extending into said epitaxial region from an upper surface of said epitaxial layer; an insulating layer lining at least a portion of said trench; a conductive region within said trench adjacent said insulating layer; a doped region of said first conductivity type formed within said epitaxial layer between a bottom portion of said trench and said substrate, said doped region having a majority carrier concentration that is lower than that of said substrate and higher than that of said epitaxial layer; a body region of a second conductivity type formed within an upper portion of said epitaxial layer and adjacent said trench, said body region extending to a lesser depth from said upper surface of said epitaxial layer than does said trench; and a source region of said first conductivity type formed within an upper portion of said body region and adjacent said trench.
2. The trench MOSFET device of claim 1 , wherein said doped region extends more than 50%) of the distance from said trench bottom to said substrate.
3. The trench MOSFET device of claim 2, wherein said doped region spans 100% of the distance from said trench bottom to said substrate.
4. The trench MOSFET device of claim 1, wherein said first conductivity type is n-type conductivity and said second conductivity type is p-type conductivity.
5. The trench MOSFET device of claim 4, wherein said doped region is doped with phosphorous.
6. The trench MOSFET device of claim 4, wherein said substrate is an N+ substrate, said epitaxial layer is an N- epitaxial layer, said doped region is an N region, said body region is a P region, said source region is an N+ region, and.
7. The trench MOSFET device of claim 1, wherein said trench MOSFET device is a silicon device.
8. The trench MOSFET device of claim 7, wherein said first insulating layer is a silicon oxide layer.
9. The trench MOSFET device of claim 7, wherein the conductive region is a doped polycrystalline silicon region.
10. The trench MOSFET device of claim 1, wherein the doped region ranges from 1 to 6 microns in thickness.
11. The trench MOSFET device of claim 4, wherein the doped region has a net n-type carrier concentration ranging from 1 x10 IS to 5 xl01 Q cm" ^ .
12. The trench MOSFET device of claim 1, wherein said trenches define a plurality of square-shaped or hexagonal-shaped MOSFET cells.
13. A trench MOSFET device comprising: a silicon substrate of n-type conductivity; a silicon epitaxial layer of n-type conductivity over said substrate, said epitaxial layer having a lower majority carrier concentration than said substrate; a trench extending into said epitaxial region from an upper surface of said epitaxial layer; a silicon oxide insulating layer lining at least a portion of said trench; a doped polycrystalline silicon region within said trench adjacent said silicon oxide layer; a doped region of n-type conductivity provided between a bottom portion of said trench and said substrate, said doped region having a majority carrier concentration that is lower than that of said substrate and higher than that of said epitaxial layer; a body region of p-type conductivity formed within an upper portion of said epitaxial layer and adjacent said trench, said body region extending to a lesser depth from said upper surface of said epitaxial layer than does said trench; and a source region of n-type conductivity formed within an upper portion of said body region and adjacent said trench.
14. The trench MOSFET device of claim 13, wherein said doped region spans 100% of the distance from said trench bottom to said substrate.
15. The trench MOSFET device of claim 13, wherein said doped region is doped with phosphorous.
16. The trench MOSFET device of claim 13, wherein the doped region ranges from 1 to 6 microns in thickness.
17. The trench MOSFET device of claim 13, wherein the doped region has a net n-type carrier concentration ranging from 1 xlO18 to 5 xlO19 cm"3.
18. A method of forming a trench MOSFET device comprising: providing a substrate of a first conductivity type; depositing an epitaxial layer of said first conductivity type over said substrate, said epitaxial layer having a lower majority carrier concentration than said substrate; forming a body region of a second conductivity type within an upper portion of said epitaxial layer; etching a trench extending into said epitaxial region from an upper surface of said epitaxial layer, said trench extending to a greater depth from said upper surface of said epitaxial layer than does said body region; forming a doped region of said first conductivity type between a bottom portion of said trench and said substrate, said doped region having a majority carrier concentration that is lower than that of said substrate and higher than that of said epitaxial layer; forming an insulating layer lining at least a portion of said trench; forming a conductive region within said trench adjacent said insulating layer; and forming a source region of said first conductivity type within an upper portion of said body region and adjacent said trench.
19. The method of claim 18, wherein said step of forming said doped region comprises:
(a) implanting a dopant of said first conductivity type into said epitaxial region; and
(b) diffusing dopant of said first conductivity type at elevated temperature.
20. The method of claim 19, wherein said dopant is diffused until the doped region spans more than 50% of the distance from said trench bottom to said substrate.
21. The method of claim 19, wherein said dopant is diffused until the doped region spans 100% of the distance from said trench bottom to said substrate.
22. The method of claim 19, wherein said first conductivity type is n-type conductivity and said second conductivity type is p-type conductivity.
23. The method of claim 22, wherein said dopant is phosphorous.
24. The method of claim 18, wherein said steps of forming said trenches and forming said doped region comprise: (a) forming a trench mask on said epitaxial layer; (b) etching said ttench through said trench mask; (c) implanting a dopant of said first conductivity type through said trench mask; and (c) diffusing said dopant of said first conductivity type at elevated temperature.
25. The method of claim 24, wherein said elevated temperature is provided by a step in which a sacrificial oxide is grown along walls of said trench.
26. The method of claim 18, wherein said trench MOSFET device is a silicon device.
27. The method of claim 18, further comprising: forming a metallic drain contact adjacent said semiconductor substrate, forming a metallic source contact adjacent an upper surface of said source region, and forming a metallic gate contact adjacent an upper surface of said conductive region remote from said source region.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100541139B1 (en) * 2003-10-02 2006-01-11 주식회사 케이이씨 Trench MOS and its manufacturing method
JP2006156461A (en) * 2004-11-25 2006-06-15 Shindengen Electric Mfg Co Ltd Semiconductor device and its manufacturing method
JP2007173675A (en) * 2005-12-26 2007-07-05 Toyota Central Res & Dev Lab Inc Semiconductor device and its manufacturing method

Families Citing this family (51)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7009247B2 (en) * 2001-07-03 2006-03-07 Siliconix Incorporated Trench MIS device with thick oxide layer in bottom of gate contact trench
US7291884B2 (en) * 2001-07-03 2007-11-06 Siliconix Incorporated Trench MIS device having implanted drain-drift region and thick bottom oxide
US20060038223A1 (en) * 2001-07-03 2006-02-23 Siliconix Incorporated Trench MOSFET having drain-drift region comprising stack of implanted regions
US7033876B2 (en) * 2001-07-03 2006-04-25 Siliconix Incorporated Trench MIS device having implanted drain-drift region and thick bottom oxide and process for manufacturing the same
US6784505B2 (en) * 2002-05-03 2004-08-31 Fairchild Semiconductor Corporation Low voltage high density trench-gated power device with uniformly doped channel and its edge termination technique
US6919599B2 (en) * 2002-06-28 2005-07-19 International Rectifier Corporation Short channel trench MOSFET with reduced gate charge
US7576388B1 (en) 2002-10-03 2009-08-18 Fairchild Semiconductor Corporation Trench-gate LDMOS structures
US7638841B2 (en) 2003-05-20 2009-12-29 Fairchild Semiconductor Corporation Power semiconductor devices and methods of manufacture
JP3954541B2 (en) * 2003-08-05 2007-08-08 株式会社東芝 Semiconductor device and manufacturing method thereof
US7368777B2 (en) 2003-12-30 2008-05-06 Fairchild Semiconductor Corporation Accumulation device with charge balance structure and method of forming the same
US7045857B2 (en) * 2004-03-26 2006-05-16 Siliconix Incorporated Termination for trench MIS device having implanted drain-drift region
US7352036B2 (en) 2004-08-03 2008-04-01 Fairchild Semiconductor Corporation Semiconductor power device having a top-side drain using a sinker trench
US7262111B1 (en) * 2004-09-07 2007-08-28 National Semiconductor Corporation Method for providing a deep connection to a substrate or buried layer in a semiconductor device
KR100582374B1 (en) * 2004-09-08 2006-05-22 매그나칩 반도체 유한회사 High voltage transistor and method for fabricating the same
DE112006000832B4 (en) 2005-04-06 2018-09-27 Fairchild Semiconductor Corporation Trenched gate field effect transistors and methods of forming the same
AT504289A2 (en) * 2005-05-26 2008-04-15 Fairchild Semiconductor TRENCH-GATE FIELD EFFECT TRANSISTORS AND METHOD FOR MAKING THE SAME
DE112006001516T5 (en) 2005-06-10 2008-04-17 Fairchild Semiconductor Corp. Field effect transistor with charge balance
CN101443889B (en) * 2006-05-12 2012-08-29 维西埃-硅化物公司 Power metal semiconductor field effect transistor contact metallization
US7319256B1 (en) 2006-06-19 2008-01-15 Fairchild Semiconductor Corporation Shielded gate trench FET with the shield and gate electrodes being connected together
US7750398B2 (en) * 2006-09-26 2010-07-06 Force-Mos Technology Corporation Trench MOSFET with trench termination and manufacture thereof
JP4294050B2 (en) * 2006-12-27 2009-07-08 三洋電機株式会社 Semiconductor device and manufacturing method thereof
DE102007014038B4 (en) 2007-03-23 2015-02-12 Infineon Technologies Austria Ag Method for producing a semiconductor component
US7615847B2 (en) * 2007-03-23 2009-11-10 Infineon Technologies Austria Ag Method for producing a semiconductor component
DE102007029121B3 (en) 2007-06-25 2008-11-20 Infineon Technologies Austria Ag Method for producing a semiconductor component, and semiconductor component
CN101868856B (en) 2007-09-21 2014-03-12 飞兆半导体公司 Superjunction structures for power devices and methods of manufacture
US7772668B2 (en) 2007-12-26 2010-08-10 Fairchild Semiconductor Corporation Shielded gate trench FET with multiple channels
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JP2010219109A (en) * 2009-03-13 2010-09-30 Sanken Electric Co Ltd Trench gate type semiconductor device, and method of manufacturing the same
DE102009021485B4 (en) * 2009-05-15 2017-10-05 Globalfoundries Dresden Module One Llc & Co. Kg Semiconductor device having a metal gate and a silicon-containing resistor formed on an insulating structure and method for its production
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US8432000B2 (en) 2010-06-18 2013-04-30 Fairchild Semiconductor Corporation Trench MOS barrier schottky rectifier with a planar surface using CMP techniques
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US20120126341A1 (en) * 2010-11-23 2012-05-24 Microchip Technology Incorporated Using low pressure epi to enable low rdson fet
US8823090B2 (en) 2011-02-17 2014-09-02 International Business Machines Corporation Field-effect transistor and method of creating same
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US9006063B2 (en) * 2013-06-28 2015-04-14 Stmicroelectronics S.R.L. Trench MOSFET
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5442214A (en) * 1994-08-09 1995-08-15 United Microelectronics Corp. VDMOS transistor and manufacturing method therefor
US6084268A (en) * 1996-03-05 2000-07-04 Semiconductor Components Industries, Llc Power MOSFET device having low on-resistance and method

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4893160A (en) 1987-11-13 1990-01-09 Siliconix Incorporated Method for increasing the performance of trenched devices and the resulting structure
US5072266A (en) 1988-12-27 1991-12-10 Siliconix Incorporated Trench DMOS power transistor with field-shaping body profile and three-dimensional geometry
JP2635828B2 (en) * 1991-01-09 1997-07-30 株式会社東芝 Semiconductor device
JPH0621468A (en) * 1992-06-29 1994-01-28 Toshiba Corp Insulated gate semiconductor device
US5410170A (en) 1993-04-14 1995-04-25 Siliconix Incorporated DMOS power transistors with reduced number of contacts using integrated body-source connections
JP3400846B2 (en) 1994-01-20 2003-04-28 三菱電機株式会社 Semiconductor device having trench structure and method of manufacturing the same
EP0948818B1 (en) 1996-07-19 2009-01-07 SILICONIX Incorporated High density trench dmos transistor with trench bottom implant
JP3915180B2 (en) * 1997-07-03 2007-05-16 富士電機デバイステクノロジー株式会社 Trench type MOS semiconductor device and manufacturing method thereof
US6262453B1 (en) * 1998-04-24 2001-07-17 Magepower Semiconductor Corp. Double gate-oxide for reducing gate-drain capacitance in trenched DMOS with high-dopant concentration buried-region under trenched gate
JP2000269487A (en) * 1999-03-15 2000-09-29 Toshiba Corp Semiconductor device and its manufacture
JP2001036071A (en) * 1999-07-16 2001-02-09 Toshiba Corp Manufacture for semiconductor device
JP2001102576A (en) * 1999-09-29 2001-04-13 Sanyo Electric Co Ltd Semiconductor device
US6285060B1 (en) * 1999-12-30 2001-09-04 Siliconix Incorporated Barrier accumulation-mode MOSFET

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5442214A (en) * 1994-08-09 1995-08-15 United Microelectronics Corp. VDMOS transistor and manufacturing method therefor
US6084268A (en) * 1996-03-05 2000-07-04 Semiconductor Components Industries, Llc Power MOSFET device having low on-resistance and method

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100541139B1 (en) * 2003-10-02 2006-01-11 주식회사 케이이씨 Trench MOS and its manufacturing method
JP2006156461A (en) * 2004-11-25 2006-06-15 Shindengen Electric Mfg Co Ltd Semiconductor device and its manufacturing method
JP2007173675A (en) * 2005-12-26 2007-07-05 Toyota Central Res & Dev Lab Inc Semiconductor device and its manufacturing method

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US7094640B2 (en) 2006-08-22

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