Claims
- 1. A semiconductor device having a reduced reverse short-channel effect, comprising:
- a semiconductor substrate of a first conductivity type;
- a gate oxide film formed on said semiconductor substrate;
- a gate electrode formed on said gate oxide film; and
- source and drain regions of a second conductivity type formed in said substrate in self-alignment with said gate electrode with a channel region thereby defined in said substrate between said source and drain regions; wherein
- at least said drain region of said source and drain regions comprises a first region formed by a first implantation of a first impurity at a dosage of approximately 3.times.10.sup.15 ions per cm.sup.2, a second region formed by a second implantation of the first impurity at a dosage of approximately 4.times.10.sup.14 ions per cm.sup.2 and by a first implantation of a second impurity at a dosage of approximately 2.times.10.sup.13 ions per cm.sup.2, whereby the reverse short-channel effect is reduced.
- 2. The semiconductor device of claim 1 wherein said second region comprises a first portion and a second portion and wherein said second portion includes said first portion.
- 3. The semiconductor device of claim 2, wherein said first portion contains ions of said first impurity implanted at a dosage of approximately 4.times.10.sup.14 ions per cm.sup.2 and wherein said second portion contains ions of said second impurity implanted at a dosage of approximately 2.times.10.sup.13 ions per cm.sup.2.
- 4. The semiconductor device of claim 3, wherein said second portion of said second region is adjacent to an end of said channel region.
- 5. The semiconductor device of claim 2, wherein said first impurity is arsenic.
- 6. The semiconductor device of claim 5, wherein said second impurity is phosphorus.
- 7. The semiconductor device of claim 6, further comprising a sidewall spacer formed on each side of said gate electrode.
Parent Case Info
This application is a continuation, of application Ser. No. 08/621,420 filed Mar. 25, 1996, now abandoned.
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Continuations (1)
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Number |
Date |
Country |
Parent |
621420 |
Mar 1996 |
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