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US5733811A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for fabricating vertical type mosfet

Assignee: NEC Electronics Corp
•
Filing: 1995-04-11
•
Granted: 1998-03-31
•
Expires: 2015-04-11
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Abstract

Abstract An epitaxial layer of a first conductivity type is grown on a main surface of a semiconductor substrate of the first conductivity type. After a gate oxide film is formed on the entire surface of the epitaxial layer, a gate electrode made of polysilicon and having a plurality of stripe sections and an electrode leading-out section is formed. Then, ions are implanted using a first resist and the gate electrode and a deep well of a second conductivity type for raising a drain breakdown characteristic is formed in the surface region of the epitaxial layer by conducting a thermal oxidation process. After ions are implanted using a second resist and the gate electrode, a plurality of bases of the second conductivity type are formed in the surface region of the epitaxial layer by conducting a thermal oxidation process. These bases are connected with one another immediately below a part of each stripe section which part is near the electrode leading-out section of the gate electrode. This arrangement of a vertical MOSFET prevents the inversion of the P-type well to N-type.

Inventors

  • 👤 Kazuzi Yamazaki

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 06:55
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/64; H10D30/66; H10D62/00; H10D62/10; H10D62/17; H10D62/393; H10D62/124; H10D62/126; H10D62/127

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 191 words
A method for fabricating a vertical MOSFET, said method comprising the steps of: growing an epitaxial layer of a first conductivity type on a main surface of a semiconductor substrate of said first conductivity type; forming a gate oxide film on the entire surface of said epitaxial layer; forming, on said gate oxide film, a gate electrode made of polysilicon and having a plurality of stripe sections and an electrode leading-out section, said plurality of stripe sections extending from said electrode leading-out section; forming, after first ions are implanted using a first resist and said gate electrode as a mask, a plurality of wells of a second conductivity type in a surface region of said epitaxial layer by conducting a thermal oxidation process; and forming, after second ions are implanted using a second resist and said gate electrode as a mask, a plurality of bases of said second conductivity type each connected with another immediately below a part of each of said plurality of stripe sections which is adjacent said electrode leading-out section of said gate electrode, in a surface region of said epitaxial layer by conducting a thermal oxidation process.
Claim 2
Independent Claim 191 words
A method for fabricating a vertical MOSFET, said method comprising the steps of: growing an epitaxial layer of a first conductivity type on a main surface of a semiconductor substrate of said first conductivity type; forming a gate oxide film on the entire surface of said epitaxial layer; forming, on said gate oxide film, a gate electrode made of polysilicon and having a plurality of stripe sections and an electrode leading-out section, said plurality of stripe sections extending from said electrode leading-out section; forming, after first ions are implanted using a first resist and said gate electrode as a mask, a plurality of wells of a second conductivity type in a surface region of said epitaxial layer by conducting a thermal oxidation process; and forming, after second ions are implanted using a second resist and said gate electrode as a mask, a plurality of bases of said second conductivity type each connected with another immediately below a part of each of said plurality of stripe sections which is adjacent said electrode leading-out section of said gate electrode, in a surface region of said epitaxial layer by conducting a thermal oxidation process.
Claim 3
Dependent Claim 28 words
A method for fabricating a vertical MOSFET according to claim 1, in which said first conductivity type is an N-type and said second conductivity type is a P-type.
Claim 4
Dependent Claim 40 words
A method for fabricating a vertical MOSFET according to claim 1, in which said ions first and second are implanted from both sides of each of said plurality of stripe sections adjacent said electrode leading-out section of said gate electrode.
Claim 5
Dependent Claim 39 words
A method for fabricating a vertical MOSFET according to claim 1, further comprising a step of forming an opening at a portion of each of said stripe sections which is adjacent said electrode leading-out section of said gate electrode.

References Cited (Backward Citations)

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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2001-03-30 2001-09-29 2002-03-31 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2005-03-30 2005-09-29 2006-03-31 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2009-03-30 2009-09-29 2010-03-31 $7700.00 Window Closed / Lapsed

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