Claims
- 1. A transistor structure comprising:
- a substrate of a first conductivity type;
- a drift region overlying the substrate and of the first conductivity type and doped to a concentration less than that of the substrate;
- a body region of a second conductivity type opposite that of the first conductivity type overlying the drift region, and defining a principal surface of the transistor structure wherein the body region includes a channel portion in contact with a side of the trench near the principal surface, and a deep body portion more heavily doped than the channel portion and spaced apart from a side of the trench;
- a conductive gate electrode extending in a trench from the principal surface through the body region and into the drift region to a depth less than that of the body region;
- a source region of the first conductivity type extending into the body region from the principal surface; and
- a trench bottom region of the first conductivity type and of a higher doping concentration than the drift region, and extending from a bottom of the trench into the drift region as deeply as does the deep body portion of the body region and spaced apart from the body region.
- 2. The transistor structure of claim 1, wherein the trench bottom region has a doping concentration in a range of 1.times.10.sup.16 /cm.sup.3 to 8.times.10.sup.16 /cm.sup.3.
- 3. The transistor of claim 1, wherein the trench bottom region has a doping concentration at least four times that of the drift region.
- 4. The transistor structure of claim 1, wherein the trench bottom region is laterally spaced apart from the deep body portion of the body region.
- 5. The transistor structure of claim 1, wherein the trench bottom region extends at least 0.5 .mu.m into the drift region from the bottom of the trench.
- 6. The transistor structure of claim 1, wherein the trench bottom region is spaced apart from the substrate by at least 1 .mu.m.
Parent Case Info
This application is a continuation of application Ser. No. 08/684,363, filed Jul. 19, 1996, now abandoned.
US Referenced Citations (11)
Foreign Referenced Citations (2)
Number |
Date |
Country |
56-58267 |
May 1981 |
JPX |
405343691 |
Dec 1993 |
JPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
684363 |
Jul 1996 |
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