BiCDMOS structure
First Claim
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1. A lateral transistor structure, comprising:
- a first semiconductor layer being of a semiconductor material of a first conductivity type;
a second semiconductor layer disposed on said first semiconductor layer, said second semiconductor layer having an upper surface;
a field oxide layer disposed on said upper surface of said second semiconductor layer;
a field implant region disposed underneath said field oxide layer, said field implant region being of a semiconductor material of said first conductivity type, said field implant region being lightly doped;
a drain region extending into said second semiconductor layer from said upper surface of said second semiconductor layer, said drain region contacting said field implant region, said drain region being of a semiconductor material of said first conductivity type;
a source region extending into said second semiconductor layer from said upper surface of said second semiconductor layer, said source region being laterally separated from said field implant region, said source region being of a semiconductor material of said first conductivity type;
a body contact region extending into said second semiconductor layer from said upper surface of said second semiconductor layer, said body contact region contacting said source region, said source region being disposed between said body contact region and said field implant region, said body contact region being of a semiconductor material of a second conductivity type opposite said first conductivity type;
a body region extending from said body contact region and underneath said source region, said body region extending between said source region and said field implant region to form a channel region at said upper surface of the second semiconductor layer between said source region and said field implant region, said body region being separated from said field implant region by a drift region portion of said second semiconductor layer between said source region and said field implant region, said body contact region being of a semiconductor material of said second conductivity type; and
a polysilicon gate layer, said polysilicon gate layer extending from a location over said source region, over said channel region, and over said drift region portion of said second semiconductor layer.
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Abstract
A process is disclosed which simultaneously forms high quality complementary bipolar transistors, relatively high voltage CMOS transistors, relatively low voltage CMOS transistors, DMOS transistors, zener diodes and thin-film resistors, or any desired combination of these, all on the same integrated circuit chip. The process uses a small number of masking steps, forms high performance transistor structures, and results in a high yield of functioning die. Isolation structures, bipolar transistor structures, CMOS transistor structures, DMOS transistor structures, zener diode structures, and thin-film resistor structures are also disclosed.
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Citations
15 Claims
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1. A lateral transistor structure, comprising:
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a first semiconductor layer being of a semiconductor material of a first conductivity type; a second semiconductor layer disposed on said first semiconductor layer, said second semiconductor layer having an upper surface; a field oxide layer disposed on said upper surface of said second semiconductor layer; a field implant region disposed underneath said field oxide layer, said field implant region being of a semiconductor material of said first conductivity type, said field implant region being lightly doped; a drain region extending into said second semiconductor layer from said upper surface of said second semiconductor layer, said drain region contacting said field implant region, said drain region being of a semiconductor material of said first conductivity type; a source region extending into said second semiconductor layer from said upper surface of said second semiconductor layer, said source region being laterally separated from said field implant region, said source region being of a semiconductor material of said first conductivity type; a body contact region extending into said second semiconductor layer from said upper surface of said second semiconductor layer, said body contact region contacting said source region, said source region being disposed between said body contact region and said field implant region, said body contact region being of a semiconductor material of a second conductivity type opposite said first conductivity type; a body region extending from said body contact region and underneath said source region, said body region extending between said source region and said field implant region to form a channel region at said upper surface of the second semiconductor layer between said source region and said field implant region, said body region being separated from said field implant region by a drift region portion of said second semiconductor layer between said source region and said field implant region, said body contact region being of a semiconductor material of said second conductivity type; and a polysilicon gate layer, said polysilicon gate layer extending from a location over said source region, over said channel region, and over said drift region portion of said second semiconductor layer. - View Dependent Claims (2, 3, 13, 14, 15)
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4. A lateral transistor structure, comprising:
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a substrate layer of a semiconductor material of a first conductivity type; an epitaxial layer of a semiconductor material of a second conductivity type opposite said first conductivity type, said epitaxial layer disposed over said substrate layer, said epitaxial layer having an upper surface; a first buried region extending downward into said substrate layer and also extending upward into said epitaxial layer, said first buried region having an upper surface disposed below said upper surface of said epitaxial layer, said first buried region being of a semiconductor material of said second conductivity type; a drain region extending downward into said epitaxial layer from said upper surface of said epitaxial layer, said drain region being of a semiconductor material of said second conductivity type; a sinker region extending downward into said epitaxial layer from said drain region, said sinker region contacting said buried region, said sinker region being of a semiconductor material of said second conductivity type; a lightly doped drain region extending downward into said epitaxial layer from said upper surface of said epitaxial layer, said lightly doped drain region contacting said drain region and extending laterally over said first buried region along said upper surface of said epitaxial layer from said drain region, said lightly doped drain region being of a semiconductor material of said second conductivity type, said lightly doped drain region being more lightly doped than said drain region; a body region extending downward into said epitaxial layer from said upper surface of said epitaxial layer, said body region being of a semiconductor material of said first conductivity type, said body region being separated from said lightly doped drain region by a drift region portion of said epitaxial layer; a source region extending downward into said body region from said upper surface of said epitaxial layer, said source region being separated from said drift region portion of said epitaxial layer by a channel region of said body region, said source region being of a semiconductor material of said second conductivity type; a body contact region extending downward into said body region from said upper surface of said epitaxial layer, said body contact region being separated from a channel region of said body region by said source region, said body contact region being of a semiconductor material of said first conductivity type; and a polysilicon gate layer disposed over said channel region and over said drift region portion of said epitaxial layer. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12)
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Specification