Claims
- 1. A conductivity-modulation field effect transistor comprising:
- a substrate having a surface;
- a base layer of a first conductivity type which is provided in a first selected region of the substrate surface;
- a source layer of a second conductivity type which is formed in said base layer;
- a drain layer of the first conductivity type which is formed in a second selected region of said substrate surface;
- a drain separation layer formed in said substrate surface so as to surround said drain layer;
- a gate electrode insulatively disposed above said substrate, for covering a certain surface portion of said base layer which is positioned adjacent to said source layer thereby to define a channel region below said gate electrode; and
- a lightly-doped semiconductor diffusion layer of the second conductivity type which is provided in said substrate surface so as to overlap said base layer and said drain separation layer, said diffusion layer having an impurity density which is varied continuously through the thickness of the diffusion layer.
- 2. The transistor according to claim 1, wherein said semiconductor diffusion layer is formed so as to overlap said base layer substantially in the overall region thereof.
- 3. The transistor according to claim 1, wherein said semiconductor diffusion layer is formed so as to partially overlap said base layer.
- 4. The transistor according to claim 1, further comprising:
- a source electrode formed on said first selected region of said substrate and electrically connected with said base layer and said source layer;
- a drain electrode formed in said second selected region of said substrate and electrically connected with said drain layer; and
- a high resistivity layer insulatively provided above said substrate and electrically connected with said gate electrode and said drain electrode.
- 5. A conductivity-modulation field effect transistor comprising:
- a semiconductive layer having a surface;
- a base layer of a first conductivity type which is provided in a first selected region of the layer surface;
- a source layer of a second conductivity type which is formed in said base layer;
- a drain layer of the first conductivity type which is formed in a second selected region of said layer surface;
- a drain separation layer formed in said layer surface so as to surround said drain layer;
- a gate electrode insulatively disposed above said semiconductive layer, for covering a certain surface portion of said base layer which is positioned adjacent to said source layer thereby to define a channel region below said gate electrode; and
- a lightly-doped semiconductor diffusion layer of the second conductivity type which is provided in said layer surface so as to overlap said base layer and said drain separation layer, said diffusion layer having an impurity density which varies continuously through the thickness of said diffusion layer.
- 6. A conductivity-modulation field effect transistor comprising:
- a semiconductive layer having a surface;
- a base layer of a first conductivity type which is provided in a first selected region of the layer surface;
- a source layer of a second conductivity type which is formed in said base layer;
- a drain layer of the first conductivity type which is formed in a second selected region of said layer surface;
- a gate electrode insulatively disposed above said semiconductive layer, for covering a certain surface portion of said base layer which is positioned adjacent to said source layer thereby to define a channel region below said gate electrode; and
- a lightly doped semiconductor diffusion layer of the second conductivity type which is provided in said layer surface so as to overlap said base layer and said drain layer, said diffusion layer having an impurity density which varies continuously through the thickness of said diffusion layer.
Priority Claims (6)
Number |
Date |
Country |
Kind |
62-41309 |
Feb 1987 |
JPX |
|
62-110743 |
May 1987 |
JPX |
|
62-304634 |
Dec 1987 |
JPX |
|
63-199538 |
Aug 1988 |
JPX |
|
1-18309 |
Jan 1989 |
JPX |
|
1-187393 |
Jul 1989 |
JPX |
|
Parent Case Info
This is a continuation of application Ser. No. 07/399,342, filed on Aug. 25, 1989, now U.S. Pat. No. 5,105,245 which is a continuation-in-part of application Ser. No. 07/233,425, filed on Aug. 18, 1988, now abandoned, which is a continuation-in-part of application Ser. No. 07/160,277filed on Feb. 25, 1988, now U.S. Pat. No. 4,980,743.
US Referenced Citations (10)
Foreign Referenced Citations (11)
Number |
Date |
Country |
0224269 |
Jun 1987 |
EPX |
58-97866 |
Jun 1983 |
JPX |
60-196974 |
Oct 1985 |
JPX |
60-254658 |
Dec 1985 |
JPX |
61-82477 |
Apr 1986 |
JPX |
61-123184 |
Jun 1986 |
JPX |
63-80569 |
Apr 1988 |
JPX |
2-156572 |
Jun 1990 |
JPX |
2-224274 |
Sep 1990 |
JPX |
2-267969 |
Nov 1990 |
JPX |
2150746 |
Jul 1985 |
GBX |
Non-Patent Literature Citations (3)
Entry |
IEEE Transactions on Electron Devices, vol. ED-33, No. 12, Dec. 1986, "n-Channel Lateral Insulated Gate Transistors: Part I-Steady-State Characteristics", by Pattanayak et al., p. 1956-p. 1963. |
IEEE Transactions on Electron Devices, vol. 38, No. 2, Feb. 1991, "Interaction Between Monolithic, Junction-Isolated Lateral Insulated-Gate Bipolar Transistors" by Chow et al., p. 310-p. 313. |
"Improved COMFETs with Fast Switching Speed and High-Current Capability" A. M. Goodman et al, RCA Laboratories, Princeton, NJ 08540 and RCA Solid State Division, Mountainton, PA 18707, CH1973-7/83/0000-0079, 1983 IEEE. |
Continuations (1)
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Number |
Date |
Country |
Parent |
399342 |
Aug 1989 |
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Continuation in Parts (2)
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Number |
Date |
Country |
Parent |
233425 |
Aug 1988 |
|
Parent |
160277 |
Feb 1988 |
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