IGBT STRUCTURE FOR WIDE BAND-GAP SEMICONDUCTOR MATERIALS
An IGBT device includes an IGBT stack, a collector contact, a gate contact, and an emitter contact. The IGBT stack includes an injector region, a drift region over the injector region, a spreading region over the drift region, and a pair of junction implants in the spreading region. The spreading region provides a first surface of the IGBT stack, which is opposite the drift region. The pair of junction implants is separated by a channel, and extends from the first surface of the IGBT stack along a lateral edge of the IGBT stack towards the drift region to a first depth, such that the thickness of the spreading region is at least one and a half times greater than the first depth.
1 . An insulated gate bipolar transistor (IGBT) device comprising:
an IGBT stack, wherein the IGBT stack includes:
an injector region;
a drift region over the injector region;
a spreading region over the drift region, the spreading region providing a first surface of the IGBT stack opposite the drift region; and
a pair of junction implants in the spreading region, wherein:
the pair of junction implants are separated by a channel and extend from the first surface of the IGBT stack along a lateral edge of the IGBT stack towards the drift region to a first depth; and
the thickness of the spreading region is at least one and a half times greater than the first depth;
a gate contact and an emitter contact on the first surface of the IGBT stack; and
a collector contact on a second surface of the IGBT stack, which is provided by the injector region opposite the drift region.
2 . The IGBT device of claim 1 wherein the thickness of the spreading region is less than four times greater than the first depth.
3 . The IGBT device of claim 1 wherein the thickness of the spreading region is at least two times greater than the first depth.
4 . The IGBT device of claim 1 wherein the IGBT stack is a wide band-gap semiconductor material.
5 . The IGBT device of claim 1 wherein the IGBT stack is Silicon Carbide (SiC).
6 . The IGBT device of claim 1 wherein each one of the pair of junction implants comprises:
a base well;
a source well; and
an ohmic well, wherein the doping concentration of the base well, the source well, and the ohmic well are different from one another.
7 . The IGBT device of claim 6 wherein:
the gate contact partially overlaps and runs between each source well in the pair of junction implants; and
the emitter contact partially overlaps both the source well and the ohmic well in each one of the pair of junction implants, respectively, without contacting the gate contact.
8 . The IGBT device of claim 7 further comprising a gate oxide layer between the gate contact and the first surface of the IGBT stack.
9 . The IGBT device of claim 1 wherein:
the drift region is a lightly doped N region;
the injector region is a highly doped P region; and
the spreading region is a highly doped N region.
10 . The IGBT device of claim 1 wherein:
the drift region is a lightly doped P region;
the injector region is a highly doped N region; and
the spreading region is a highly doped P region.
11 . The IGBT device of claim 1 wherein:
the first depth is in the range of about 0.3 μm to about 1.0 μm; and
the thickness of the spreading region is in the range of about 1.5 μm to about 10 μm.
12 . The IGBT device of claim 1 wherein a width of the IGBT stack is between about 1 μm to 4 μm.
13 . An insulated gate bipolar transistor (IGBT) device comprising:
an IGBT stack, wherein the IGBT stack includes:
an injector region;
a drift region over the injector region;
a spreading region over the drift region, the spreading region providing a first surface of the IGBT stack opposite the drift region; and
a pair of junction implants in the spreading region, wherein:
the pair of junction implants are separated by a junction field-effect transistor (JFET) region and extend from the first surface of the IGBT stack along a lateral edge of the IGBT stack towards the drift region to a first depth; and
the spreading region extends beyond the first depth by at least 1.5 μm;
a gate contact and an emitter contact on the first surface of the IGBT stack; and
a collector contact on a second surface of the IGBT stack, which is provided by the injector region opposite the drift region.
14 . The IGBT device of claim 13 wherein the spreading region extends beyond the first depth by less than about 10.0 μm.
15 . The IGBT device of claim 13 wherein the spreading region extends beyond the first depth by at least 2.0 μm.
16 . The IGBT device of claim 13 wherein the IGBT stack comprises a wide band-gap semiconductor material.
17 . The IGBT device of claim 13 wherein the IGBT stack comprises Silicon Carbide (SiC).
18 . The IGBT device of claim 13 wherein each one of the pair of junction implants comprises:
a base well;
a source well; and
an ohmic well, wherein the doping concentration of the base well, the source well, and the ohmic well are different from one another.
19 . The IGBT device of claim 18 wherein:
the gate contact partially overlaps and runs between each source well in the pair of junction implants; and
the emitter contact partially overlaps both the source well and the ohmic well in each one of the pair of junction implants, respectively, without contacting the gate contact.
20 . The IGBT device of claim 19 further comprising a gate oxide layer between the gate contact and the first surface of the IGBT stack.
21 . The IGBT device of claim 13 wherein:
the drift region is a lightly doped N region;
the injector region is a highly doped P region; and
the spreading region is a highly doped N region.
22 . The IGBT device of claim 13 wherein:
the drift region is a lightly doped P region;
the injector region is a highly doped N region; and
the spreading region is a highly doped P region.
23 . The IGBT device of claim 13 wherein the first depth is in the range of about 0.3 μm to about 1.5 μm.
24 . The IGBT device of claim 13 wherein a width of the IGBT stack is between about 1 μm to 4 μm.
25 . A method comprising:
providing an IGBT stack including an injector region, a drift region over the injector region, and a spreading region over the drift region, such that the spreading region provides a first surface of the IGBT stack opposite the drift layer;
providing a pair of junction implants in the first surface of the IGBT stack such that the pair of junction implants are separated by a channel and extend from a first surface of the IGBT stack towards the drift region to a first depth, wherein the thickness of the spreading region is at least one and a half times greater than the first depth;
providing a gate contact and an emitter contact on the first surface of the IGBT stack; and
providing a collector contact on a second surface of the IGBT stack, which is provided by the injector region opposite the drift region.
26 . The method of claim 25 wherein the thickness of the spreading region is less than four times greater than the first depth.
27 . The method of claim 25 wherein the thickness of the spreading region is at least two times greater than the first depth.
28 . The method of claim 25 wherein the IGBT stack is Silicon Carbide (SiC).
29 . An insulated gate bipolar transistor (IGBT) device comprising:
an IGBT stack, wherein the IGBT stack includes:
an injector region;
a drift region over the injector region;
a spreading region over the drift region; and
a pair of junction implants in the spreading region, each of the pair of junction implants separated by a channel;
wherein the spreading region enables the width of the IGBT stack to remain less than about 4 μm.