Vertical power devices having trench-based electrodes therein

• US 6,649,975 B2
• Filed: 11/05/2001
• Issued: 11/18/2003
• Est. Priority Date: 11/16/2000
• Status: Expired due to Fees

• Current Assignee: Silicon Semiconductor Corporation
• Original Assignee: Silicon Semiconductor Corporation
• Inventors: Baliga, Bantval Jayant
• Primary Examiner(s): Flynn, Nathan J.
• Assistant Examiner(s): MONDT, JOHANNES P
• Application Number:
  US09/992,104
• Publication Number:
  US 20020056884A1
• Time in Patent Office: 743 Days
• Field of Search: 257/327, 257/328, 257/329, 257/330, 257/331, 257/340, 257/342, 257/365, 257/492, 257/493, 257/288
• US Class Current: 257/330
• CPC Class Codes: H01L 2223/6627 Waveguides, e.g. microstrip line, strip line, coplanar line
• CPC Class Codes: H01L 2224/0603 Bonding areas having different sizes, e.g. different heights or widths
• CPC Class Codes: H01L 2224/06181 On opposite sides of the body
• CPC Class Codes: H01L 2224/371 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/40095 Kinked
• CPC Class Codes: H01L 2224/40245 the item being metallic
• CPC Class Codes: H01L 2224/73255 Bump and strap connectors
• CPC Class Codes: H01L 2224/73257 Bump and wire connectors
• CPC Class Codes: H01L 2224/81801 Soldering or alloying
• CPC Class Codes: H01L 2224/83801 Soldering or alloying
• CPC Class Codes: H01L 2224/84 using a strap connector
• CPC Class Codes: H01L 23/552 Protection against radiation, e.g. light or electromagnetic waves
• CPC Class Codes: H01L 23/60 Protection against electrostatic charges or discharges, e.g. Faraday shields
• CPC Class Codes: H01L 23/66 High-frequency adaptations
• CPC Class Codes: H01L 24/16 of an individual bump connector
• CPC Class Codes: H01L 24/37 of an individual strap connector
• CPC Class Codes: H01L 24/40 of an individual strap connector
• CPC Class Codes: H01L 24/41 of a plurality of strap connectors
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/73 Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• CPC Class Codes: H01L 27/088 : the components being field-effect transistors with insulated gate
• CPC Class Codes: H01L 29/0696 : of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs
• CPC Class Codes: H01L 29/402 : Field plates
• CPC Class Codes: H01L 29/407 : Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/41741 : for vertical or pseudo-vertical devices
• CPC Class Codes: H01L 29/4238 : characterised by the surface lay-out
• CPC Class Codes: H01L 29/66712 : Vertical DMOS transistors, i.e. VDMOS transistors
• CPC Class Codes: H01L 29/7802 : Vertical DMOS transistors, i.e. VDMOS transistors
• CPC Class Codes: H01L 29/7803 : structurally associated with at least one other device assemblies H01L25/00; integrated circuits H01L27/00
• 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 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 2924/00014 : 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 2924/10253 : Silicon [Si]
• CPC Class Codes: H01L 2924/1305 : Bipolar Junction Transistor [BJT]
• CPC Class Codes: H01L 2924/1306 : Field-effect transistor [FET]
• CPC Class Codes: H01L 2924/13063 : Metal-Semiconductor Field-Effect Transistor [MESFET]
• CPC Class Codes: H01L 2924/13091 : Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15787 : Ceramics, e.g. crystalline carbides, nitrides or oxides
• CPC Class Codes: H01L 2924/1903 : including wave guides
• CPC Class Codes: H01L 2924/3011 : Impedance

Abstract

Vertical power devices include a semiconductor substrate having a drift region of first conductivity type therein and first and second stripe-shaped trenches that extend in the semiconductor substrate and define a drift region mesa therebetween. First and second insulated source electrodes are provided in the first and second stripe-shaped trenches, respectively. A UMOSFET, comprising a third trench that is shallower than the first and second stripe-shaped trenches, is provided in the drift region mesa.

Claims

1. A UMOSFET, comprising:

a semiconductor substrate having a drift region of first conductivity type therein;

a first stripe-shaped trench in said semiconductor substrate;

an insulated gate electrode in said first stripe-shaped trench;

a second stripe-shaped trench that extends in said semiconductor substrate in a direction parallel to said first stripe-shaped trench, said second stripe-shaped trench having a depth that is greater than a depth of said first stripe-shaped trench;

an insulated source electrode in said second stripe-shaped trench;

a base region of second conductivity type that extends in the drift region and between opposing sidewalls of said first and second stripe-shaped trenches;

a source region of first conductivity type in said base region; and

a source electrode that extends on said semiconductor substrate and is electrically connected to said source region and to said insulated source electrode.

2. The UMOSFET of claim 1, further comprising a third stripe-shaped trench that extends in said semiconductor substrate in a direction parallel to said second stripe-shaped trench;

wherein said first stripe-shaped trench extends between said second and third stripe-shaped trenches; and

wherein a depth of said third stripe-shaped trench equals the depth of the second stripe-shaped trench.

3. A UMOSFET, comprising:

a semiconductor substrate having a drift region of first conductivity type therein;

first and second trenches that extend in said semiconductor substrate and define a drift region mesa therebetween;

first and second insulated source electrodes in said first and second trenches, respectively; and

a UMOSFET comprising a third trench that is shallower than said first and second trenches, in the drift region mesa.

4. The UMOSFET of claim 3, further comprising a first base shielding region of second conductivity type that forms a non-rectifying junction with a base region of said UMOSFET and a rectifying junction with the drift region and extends adjacent a first sidewall of said first trench.

5. The UMOSFET of claim 4, wherein said first base shielding region is self-aligned with the first sidewall of said first trench.

6. The UMOSFET of claim 3, further comprising a transition region of first conductivity type that forms a rectifying junction with a base region of said UMOSFET and a non-rectifying junction with the drift region.

7. The UMOSFET of claim 4, further comprising a transition region of first conductivity type that forms a rectifying junction with a base region of said UMOSFET and a non-rectifying junction with the drift region.

8. The UMOSFET of claim 5, further comprising a transition region of first conductivity type that forms a rectifying junction with a base region of said UMOSFET and a non-rectifying junction with the drift region.