Claims
- 1. An integrated circuit comprising:
- a semiconductive substrate having an initial high-voltage tank formed therein;
- a thin epitaxial layer formed on top of said substrate and overlying said initial high-voltage tank, said epitaxial layer having approximately a same crystal orientation and impurity concentration as said substrate, wherein said substrate has a first conductivity type, said epitaxial layer has said first conductivity type, said initial high voltage tank has a second conductivity type;
- a tank extension having said second conductivity type is formed in said epitaxial layer directly above said initial high voltage tank and is in contact with said initial high voltage tank, so that a homogeneous high voltage tank is formed;
- a high frequency bipolar transistor, having an emitter, a base, and a collector, formed in said epitaxial layer; and
- a high voltage MOS transistor formed in said homogeneous high-voltage tank.
- 2. The integrated circuit of claim 1, in which said thin epitaxial layer is less than approximately 1.75 microns thick.
- 3. The integrated circuit of claim 1, in which said high frequency bipolar transistor has an operating frequency that is greater than about 1 gigahertz.
- 4. The integrated circuit of claim 1, further comprising:
- a Diffusion Under Film, DUF, region formed in said substrate adjacent to said epitaxial layer, said DUF region being directly below said high frequency transistor and connected to said collector; and
- means for contacting said DUF region so that an electrical path having a low impedance is formed from said collector to an upper surface of said epitaxial layer.
- 5. The integrated circuit of claim 12, wherein:
- said collector forms a region of said second conductivity type in said epitaxial layer such that said collector region overlies said DUF region and is in contact with said DUF region;
- said base being formed of said first conductivity type within said collector region; and
- said emitter being formed of said second conductivity type within said base region.
- 6. The integrated circuit of claim 1, in which said high voltage MOS transistor operates in a voltage range that is selected to be between approximately 30 volts to 60 volts.
- 7. The integrated circuit of claim 1, further comprising:
- a third device formed in said epitaxial layer, said third device type is selected from the group consisting of:
- a) a sub micron CMOS device,
- b) an EEPROM device,
- c) an EPROM device,
- d) a high voltage CMOS device,
- e) a tunneling diode, and
- f) a Schottky diode.
- 8. An integrated circuit comprising:
- a semiconductive substrate having an initial high-voltage tank formed therein:
- a thin epitaxial layer formed on top of said substrate and overlying a said initial high-voltage tank, said epitaxial layer having approximately a same crystal orientation and impurity concentration as said substrate, wherein said substrate has a first conductivity type, said epitaxial layer has said first conductivity type, said initial high voltage tank has a second conductivity type, and wherein:
- a tank extension having said second conductivity type is formed in said epitaxial layer directly above said initial high voltage tank and is in contact with said initial high voltage tank, so that a homogeneous high voltage tank is formed;
- a high frequency bipolar transistor, having an emitter, a base, and a collector, formed in said epitaxial layer;
- a high voltage MOS transistor formed in said homogeneous high-voltage tank;
- said high voltage MOS transistor further comprises:
- a D-well formed in said homogenous high voltage tank, said D-well further comprising a backgate region of said first conductivity type and a source region formed within said backgate region of said second conductivity type;
- a gate structure formed above a portion of said D-well and overlying said backgate region, said gate structure comprising a conductive gate and a gate insulation layer between said gate and said D-well;
- a thick field oxide formed in said homogenous high voltage tank; and
- a drain region formed of said second conductivity type in said homogenous high voltage tank, said thick field oxide being interposed between said drain region and said gate structure.
- 9. The integrated circuit of claim 8, in which said thin epitaxial layer is less than approximately 1.75 microns thick.
- 10. The integrated circuit of claim 9, in which said high frequency bipolar transistor has an operating frequency that is greater than about 1 gigahertz.
- 11. The integrated circuit of claim 8, further comprising:
- a Diffusion Under Film, DUF, region formed in said substrate adjacent to said epitaxal layer, said DUF region being directly below said high frequency transistor and connected to said collector, and
- means for contacting said DUF region so that an electrical path having a low impedance is formed from said collector to an upper surface of said epitaxial layer.
- 12. The integrated circuit of claim 11, wherein:
- said collector forms a region of said second conductivity type in said epitaxial layer such that said collector region overlies said DUF region and is in contact with said DUF region;
- said base being formed of said first conductivity type within said collector region; and
- said emitter being formed of said second conductivity type within said base region.
- 13. The integrated circuit of claim 8, in which said high voltage MOS transistor operates in a voltage range that is selected to be between approximately 30 volts to 60 volts.
- 14. The integrated circuit of claim 8, further comprising:
- a third device formed in said epitaxial layer, said third device type is selected from the group consisting of:
- a) a sub micron CMOS device,
- b) an EEPROM device,
- c) an EPROM device,
- d) a high voltage CMOS device,
- e) a tunneling diode, and
- f) a Schottky diode.
Parent Case Info
This application is a Continuation of application Ser. No. 08/459,895, filed on Jun. 02,1995, now abandoned.
US Referenced Citations (15)
Foreign Referenced Citations (1)
Number |
Date |
Country |
2257296 |
Jan 1993 |
GBX |
Continuations (1)
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Number |
Date |
Country |
Parent |
459895 |
Jun 1995 |
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