Trench-gate semiconductor devices

• US 7,122,860 B2
• Filed: 05/21/2003
• Issued: 10/17/2006
• Est. Priority Date: 05/31/2002
• Status: Expired due to Term

• Current Assignee: Nexperia B.V. (Wingtech Technology Co., Ltd.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Grover, Raymond J., Rutter, Philip, Peake, Steven T.
• Primary Examiner(s): Wilczewski, Mary
• Assistant Examiner(s): Barnes, Seth
• Application Number:
  US10/515,748
• Publication Number:
  US 20050173758A1
• Time in Patent Office: 1,245 Days
• Field of Search: 257/330, 257/332, 257/334, 257/339
• US Class Current: 257/339
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/0603 Bonding areas having different sizes, e.g. different heights or widths
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49111 the connectors connecting two common bonding areas, e.g. Litz or braid wires
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 2224/85399 Material
• CPC Class Codes: H01L 23/49562 for devices being provided for in H01L29/00
• CPC Class Codes: H01L 23/49575 Assemblies of semiconductor devices on lead frames
• CPC Class Codes: H01L 24/06 of a plurality of bonding areas
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• CPC Class Codes: H01L 25/16 the devices being of types provided for in two or more different main groups of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. forming hybrid circuits
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/4232 with insulated gate
• CPC Class Codes: H01L 29/7397 and a gate structure lying on a slanted or vertical surface or formed in a groove, e.g. trench gate IGBT
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236
• CPC Class Codes: H01L 29/7825 with trench gate electrode trench gate electrodes per se H01L29/4236
• CPC Class Codes: H01L 29/7828 without inversion channel, e.g. vertical ACCUFETs, normally-on vertical MISFETs
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01015 : Phosphorus [P]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/12036 : PN diode
• CPC Class Codes: H01L 2924/1305 : Bipolar Junction Transistor [BJT]
• CPC Class Codes: H01L 2924/13055 : Insulated gate bipolar transistor [IGBT]
• CPC Class Codes: H01L 2924/13091 : Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding

Abstract

A trench-gate semiconductor device, for example a MOSFET or IGBT, includes a semiconductor body (20) having a drain region (4) comprising a drain drift region (4a) and a drain contact region (4b). An insulated field plate (24) is included in the trench (10) between the gate (8) and the drain contact region (4b), wherein the field plate (24) is for connection to a bias potential greater than the gate potential and near to the bulk breakdown voltage of the drain drift region (4a). The field plate (24) causes the potential drop across the drain drift region (4a) to be spread considerably more evenly, particularly at applied voltages greater than the bulk breakdown voltage, thereby substantially increasing the breakdown voltage of the device.

Claims

1. A trench-gate semiconductor device including:

a semiconductor body (20) defining a trench (10) having an insulated gate (8) therein, the semiconductor body comprising a source region (2) and a drain region (4) of a first conductivity type which are separated by a channel-accommodating region (6) adjacent to the gate, the drain region comprising a drain drift region (4a) and a drain contact region (4b), with the drain drift region between the channel-accommodating region (6) and the drain contact region (4b), and the drain drift region (4a) doped to a lesser extent than the drain contact region (4b); and

an insulated field plate (24) in the trench (10) between the gate (8) and the drain contact region (4b), wherein the field plate (24) is connected in operation to a bias source at a bias potential greater than the gate potential and near to the bulk breakdown voltage of the drain drift region (4a).

2. A device of claim 1 wherein the trench (10) extends substantially to the junction (4c) between the drain drift region (4a) and the drain contact region (4b).

3. A device of claim 1 or 2 wherein the gate (8) is shallower than the upper boundary of the drain drift region (4a) and the drain contact region (4b).

4. A device of claim 1 or claim 2 wherein the doping level of the drain drift region (4a) increases towards the drain contact region (4b).

5. A module (60) comprising a device of claim 1 or claim 2 wherein the field plate (24) is connected to an internal voltage line of the module (60).

6. A device of claim 1 or claim 2 wherein an additional external terminal (54) is provided which is electrically connected to the field plate (24).

7. A module (60) of claim 5 wherein the bias potential is around 60 or 100% of the bulk breakdown voltage of the drain drift region (4a).

8. A module 60 of claim 7 wherein the bias potential is around 80% of the bulk breakdown voltage of the drain drift region (4a).

9. A method of operating a trench-gate semiconductor device of claim 1 or claim 2, comprising applying to the field plate (24) of the device said bias potential greater than the gate potential and near to the bulk breakdown voltage of the drain drift region (4a).

10. A method of claim 9 wherein the bias potential is around 60 to 100% of the bulk breakdown voltage of the drain drift region (4a).

11. A method of claim 10 wherein the bias potential is around 80% of the bulk breakdown voltage of the drain drift region (4a).