Ion implanted JFET with self-aligned source and drain
First Claim
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1. A method for fabricating junction field effect transistors comprising:
- introducing first and second conductivity type impurities into a first surface of a substrate of said first conductivity type by ion implantation to form a top gate of said first conductivity type and a channel of said second conductivity type between a said substrate, which is a bottom gate, and said top gate;
depositing contact material including second conductivity type impurities at two spaced positions along said surface of said substrate; and
heating to simultaneously activate said ion implanted impurities to form said top gate and channel and diffuse said second conductivity type impurities from said contact material into said channel to form source and drain with self-aligned contacts.
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Abstract
A method of fabricating I2 JFETs including separately and in combination out-diffusion of impurities from doped source and drain contact material to product self-aligned source and drains; using the source and drain contacts as mask to form a self-aligned top gate spaced from the source and drain; and dual ion implantation of the channel for increasing radiation hardness.
59 Citations
22 Claims
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1. A method for fabricating junction field effect transistors comprising:
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introducing first and second conductivity type impurities into a first surface of a substrate of said first conductivity type by ion implantation to form a top gate of said first conductivity type and a channel of said second conductivity type between a said substrate, which is a bottom gate, and said top gate; depositing contact material including second conductivity type impurities at two spaced positions along said surface of said substrate; and heating to simultaneously activate said ion implanted impurities to form said top gate and channel and diffuse said second conductivity type impurities from said contact material into said channel to form source and drain with self-aligned contacts. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for fabricating junction field effect transistors comprising:
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introducing a second conductivity type impurities into a first surface of a substrate of a first conductivity type to form a channel of said second conductivity type; introducing second conductivity type impurities into said substrate through contact apertures in an insulating layer on said first surface to form spaced source and drains of said second conductivity type in said channel; depositing and patterning contact material to form a contact to said substrate through said contact apertures for said source and drain and a portion extending across said insulating layer; and introducing first conductivity type impurities into said channel using said contact material as a mask to form a top gate of said first conductivity type in said channel and spaced from said source and drain. - View Dependent Claims (13, 14)
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15. A method of fabricating complementary junction field effect transistors comprising:
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(a) selectively introducing impurities of a first conductivity type into a first bottom gate of a second conductivity type to form a first channel of a first conductivity type; (b) selectively introducing impurities of a second conductivity type into a second bottom gate of a first conductivity type to form a second channel of a second conductivity type; (c) selectively introducing impurities of a first conductivity type into said first channel to form spaced first source and first drain of said first conductivity type in said first channel; (d) selectively introducing impurities of a second conductivity type into second channel to form spaced second source and second drain of said second conductivity type in said second channel, (e) selectively introducing impurities of a second conductivity type into said first channel to form a top gate of said second conductivity type in said first channel and spaced from said first source and first drain; (f) selectively introducing impurities of a first conductivity type into said second channel to form a top gate of said first conductivity type in said second channel and spaced from said second source and second drain; (g) forming first source and drain contact apertures in a thin insulator layer over said first channel prior to step c; (h) forming second source and drain contact apertures in a thin insulator layer over said second channel prior to step d; and (i) depositing and patterning a contact material to form source and drain contacts having a portion extending across said thin insulator prior to steps e and f to be used as a mask during steps e and f to form said first and second top gate spaced from a respective source and drain. - View Dependent Claims (16, 17, 18)
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19. A method for fabricating junction field effect transistors comprising:
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introducing second conductivity type impurities into a first surface of a substrate of a first conductivity type to a first depth and first impurity concentration to form an active channel; introducing second conductivity type impurities into said substrate to a second depth and second impurity concentration less than said first depth and first impurity concentration to form an enhanced channel region at said surface of said active channel; introducing second conductivity type impurities into said substrate to form spaced source and drains of said second conductivity type in said active channel and enhanced channel region; and introducing first conductivity type impurities into said channel to form a top gate of said first conductivity type in said channel and spaced from said source and drain. - View Dependent Claims (20)
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21. A method of fabricating complementary junction field effect transistors comprising:
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(a) selectively introducing impurities of a first conductivity type into a first bottom gate of a second conductivity type to a first depth and first impurity concentration to form a first active channel of a first conductivity type; (b) selectively introducing first conductivity type impurities into said first active channel to a second depth and second impurity concentrations less than said first depth and first impurity concentration to form a first enhanced channel region at the surface of said first active channel; (c) selectively introducing impurities of second conductivity type into a second bottom gate of a first conductivity type to a third depth and third impurity concentration to form a second active channel of a second conductivity type; (d) selectively introducing second conductivity type impurities into said second active channel to a fourth depth and fourth impurity concentration less than said third depth and third impurity concentration to form a second enhanced channel region at the surface of said second active channel; (e) selectively introducing impurities of a first conductivity type into said first active channel and first enhanced channel region to form spaced first source and first drain of said first conductivity type in said first active channel; (f) selectively introducing impurities of a second conductivity type into said second active channel and second enhanced channel region to form spaced second source and second drain of said second conductivity type in said second active channel; (g) selectively introducing impurities of a second conductivity type into said first active channel and first enhanced channel region to form a top gate of said second conductivity type in said first active channel and spaced from said first source and first drain at the surface by said first enhanced channel region; and (h) selectively introducing impurities of a first conductivity type into said second active channel and second enhanced channel region to form a top gate of said first conductivity type in said second active channel and spaced from said second source and second drain at the surface by said second enhanced channel region. - View Dependent Claims (22)
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Specification