Method of forming a monolithic semiconductor integrated circuit having an N-channel JFET
First Claim
1. A method of fabricating a monolithic semiconductor integrated circuit which comprises an N-channel junction field effect transistor, complementary insulated gate field effect transistors, and a bipolar junction transistor, the method comprising the steps of:
- providing a semiconductor material of a first conductivity type and having a major surface;
forming an isolated N-channel junction field effect transistor region, an N-channel insulated gate field effect transistor region, an isolated P-channel insulated gate field effect transistor region, and an isolated bipolar junction transistor region in the semiconductor material, wherein the isolated N-channel junction field effect transistor region is contiguous with a buried layer of a second conductivity type;
forming a gate oxide layer on a portion of the major surface in the N-channel insulated gate field effect transistor region and on a portion of the major surface in the isolated P-channel insulated gate field effect transistor region;
forming a first gate conductor on the gate oxide on the portion of the major surface in the N-channel insulated gate field effect transistor region and a second gate conductor on the gate oxide on the portion of the major surface in the isolated P-channel insulated gate field effect transistor region;
forming a first source region and a first drain region in portions of the isolated N-channel junction field effect transistor region, a second source region and a second drain region in portions of the N-channel insulated gate field effect transistor region, and a collector contact region in a portion of the isolated bipolar junction transistor;
forming a third source region and a third drain region in portions of the isolated P-channel insulated gate field effect transistor region, and a gate contact region in a portion of the N-channel junction field effect transistor region;
forming a base region in another portion of the isolated bipolar junction transistor region;
forming a channel region in the N-channel junction field effect transistor region, wherein the channel region contains the first source region and the first drain region;
forming a polysilicon emitter in contact with a portion of the base region; and
forming a polysilicon gate, wherein the polysilicon gate is in contact with a portion of the channel region between the first source region and the first drain region.
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Accused Products
Abstract
An N-channel JFET (60) and a method of forming the N-channel JFET (60) in a BiCMOS process. The N-channel JFET (60) is monolithically fabricated with an N-channel IGFET (70), a P-channel IGFET (75), and an NPN BJT (80) in an epitaxial layer (21). The N-channel JFET (60) is formed in an isolated N-channel JFET region (24), the P-channel IGFET (75) is formed in an isolated P-channel IGFET region (27), and the NPN BJT (80) is formed in an isolated BJT region (29). The N-channel IGFET (70) is fabricated in a P-type well (26) that is not isolated from other N-channel IGFET'"'"'s in the epitaxial layer (21). Accordingly, the N-channel JFET (60), the N-channel IGFET (70), the P-channel IGFET (75), and an NPN BJT (80) are monolithically formed in the BiCMOS process.
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Citations
13 Claims
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1. A method of fabricating a monolithic semiconductor integrated circuit which comprises an N-channel junction field effect transistor, complementary insulated gate field effect transistors, and a bipolar junction transistor, the method comprising the steps of:
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providing a semiconductor material of a first conductivity type and having a major surface; forming an isolated N-channel junction field effect transistor region, an N-channel insulated gate field effect transistor region, an isolated P-channel insulated gate field effect transistor region, and an isolated bipolar junction transistor region in the semiconductor material, wherein the isolated N-channel junction field effect transistor region is contiguous with a buried layer of a second conductivity type; forming a gate oxide layer on a portion of the major surface in the N-channel insulated gate field effect transistor region and on a portion of the major surface in the isolated P-channel insulated gate field effect transistor region; forming a first gate conductor on the gate oxide on the portion of the major surface in the N-channel insulated gate field effect transistor region and a second gate conductor on the gate oxide on the portion of the major surface in the isolated P-channel insulated gate field effect transistor region; forming a first source region and a first drain region in portions of the isolated N-channel junction field effect transistor region, a second source region and a second drain region in portions of the N-channel insulated gate field effect transistor region, and a collector contact region in a portion of the isolated bipolar junction transistor; forming a third source region and a third drain region in portions of the isolated P-channel insulated gate field effect transistor region, and a gate contact region in a portion of the N-channel junction field effect transistor region; forming a base region in another portion of the isolated bipolar junction transistor region; forming a channel region in the N-channel junction field effect transistor region, wherein the channel region contains the first source region and the first drain region; forming a polysilicon emitter in contact with a portion of the base region; and forming a polysilicon gate, wherein the polysilicon gate is in contact with a portion of the channel region between the first source region and the first drain region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of fabricating a monolithic semiconductor structure which comprises an N-channel junction field effect transistor, an N-channel insulated gate field effect transistor, a P-channel insulated gate field effect transistor, and a bipolar junction transistor, comprising the steps of:
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providing a semiconductor material of P conductivity type having an epitaxial layer disposed thereon, the epitaxial layer having a major surface and at least three isolated regions extending from the major surface into the epitaxial layer and a P-type well extending from the major surface into the epitaxial layer, wherein a first isolated region serves as an N-channel junction field effect transistor active area, a second isolated region serves as a P-channel insulated gate field effect transistor active area, a third isolated region serves as a bipolar junction transistor active area, and the P-type well serves as an N-channel insulated gate field effect transistor active area, and wherein the first isolated region is of P conductivity type and is bounded by a dopant layer of N conductivity type; forming a first insulated gate structure on a portion of the major surface in the second isolated region and forming a second insulated gate structure on a portion of the major surface of the P-type well; forming a first source region and a first drain region in the first isolated region, a second source region and a second drain region in the P-type well, and a first doped region in the third isolated region, wherein the first and second source regions, the first and second drain regions, and the first doped region are of N conductivity type; forming a third source region and a third drain region in the second isolated region, a second doped region in the third isolated region, a first doped region in the first isolated region, wherein the third source region, the third drain region, the second doped region in the third isolated region and the first doped region in the first isolated region are of P conductivity type; forming a base region in the third isolated region, wherein the base region is of P conductivity type and encloses the second doped region; forming a channel region in the first isolated region, wherein the channel region is of N conductivity type, and encloses the first source region and the first drain region; forming an emitter in the second doped region of the third isolated region; and forming a second doped region in the channel region, the second doped region between and spaced apart from the first source region and the first drain region, wherein the first and second doped regions serve as gates for the N-channel junction field effect transistor. - View Dependent Claims (10, 11, 12, 13)
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Specification