Claims
- 1. A metal-semiconductor field-effect transistor (MESFET) comprising:
- a source region;
- a drain region having a depth that extends a first given distance from a surface of said transistor, a first net doping level, and a given width;
- a single continuous channel region having a width that extends from said source region to an area adjacent to said drain region and a depth that extends a second given distance from and perpendicular to said surface of said transistor, wherein said first given distance is substantially greater than said second given distance;
- a subchannel region having a second net doping level;
- a guard region having a depth, a first width, a second width, a third net doping level, said depth of said guard region extending a third given distance from said surface of said transistor, said third given distance being substantially grater than said first given distance, said first width of said guard region extending from said area to said drain region, said second width of said guard region extending from said area to said drain region, and said third net doping level being between said first and second net doping levels, wherein said guard region operates to increase a breakdown voltage of said transistor under an open channel condition; and
- a gate electrode of a metal material disposed directly on a surface of said single continuous channel, wherein said gate electrode is offset towards said source electrode for lowering parasitic source resistance.
- 2. The transistor according to claim 1, further comprising a source electrode disposed on said source region and a drain electrode disposed on said drain region.
- 3. The transistor according to claim 1, wherein said source region, said drain region, and said single continuous channel region are disposed on said subchannel region, and wherein said drain region and said source region each have a higher doping level than said single continuous channel region, and said guard region having a net doping level in between said net doping levels of said drain region and said subchannel region.
- 4. The transistor according to claim 1, wherein said transistor is fabricated from GaAs material.
- 5. The transistor according to claim 3, wherein said subchannel region comprises undoped GaAs material.
- 6. The transistor according to claim 3, wherein said subchannel region comprises GaAs material having a p-type doping.
- 7. The transistor according to claim 1, wherein said guard region is formed with minimal effect on doping level of said single continuous channel region, whereby the breakdown voltage is increased with minimal effect on other performance parameters of said transistor.
- 8. The transistor according to claim 1, further including a gate structure, said source region being self-aligned to said gate structure so that said source region has a lateral edge that is vertically aligned with a lateral edge of said gate structure.
- 9. The transistor according to claim 3, wherein said source region and said drain region each have n-type active carrier concentration of at least 1.times.10.sup.17 /cm.sup.3 within a depth of approximately 0.3 um from said surface of said transistor.
- 10. The transistor according to claim 9, wherein said single continuous channel region includes an n-type active carrier concentration of at least 5.times.10.sup.16 /cm.sup.3 within a depth of about 0.2 um from said surface of said transistor.
- 11. The transistor according to claim 10, wherein said guard region includes an n-type active carrier concentration of at least 1.times.10.sup.16 /cm.sup.3 within a depth of about 0.4 um from said surface of said transistor.
- 12. The transistor according to claim 11, wherein said subchannel region includes an active p-type carrier concentration of at least 1.times.10.sup.16 /cm.sup.3 within a depth of about 0.6 um from said Surface of said transistor.
Parent Case Info
This is a continuation of application Ser. No. 08/385,079, filed on Feb. 7, 1995, now abandoned entitled PLANAR ION-IMPLANTED GAAS MESFETS WITH IMPROVED OPEN-CHANNEL BURNOUT CHARACTERISTICS which is a continuation of application Ser. No. 08/253,723, filed on Jun. 3, 1994, now abandoned.
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Continuations (2)
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Number |
Date |
Country |
Parent |
385079 |
Feb 1995 |
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Parent |
253723 |
Jun 1994 |
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