US5448101A
Expired / Lapsed
US
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Semiconductor device having P channel high voltage transistors with improved breakdown voltages
Assignee: Mitsubishi Electric Corp
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Filing: 1994-07-08
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Granted: 1995-09-05
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Expires: 2014-07-08
Abstract
Abstract The present invention is primarily directed to obtaining a P channel high voltage transistor with an improved breakdown voltage. A first N type well region is provided in a main surface of a P type semiconductor substrate. A first field oxide film is provided in the main surface of the first N type well region. A P type source region and a P type drain region are provided on the opposite sides of the first field oxide film in the main surface of the first N type well region. A P type impurity injection region is provided immediately under the field oxide film so as to be connected to the P type drain region. A gate electrode is provided between the P type source region and the P type drain region on the first N type well region. An N + ion injection region is provided between the P type source region and a channel in the N type well region. The first N type well region located under the P type drain region has its N type impurity concentration uniform at any depth.
Inventors
- 👤 Atsushi Ono
- 👤 Nobuyuki Saiki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:53
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/80; H10D84/811; H10D30/00; H10D30/60; H10D30/601; H10D30/603; H10D62/00; H10D62/10; H10D62/102; H10D62/103; H10D62/105; H10D62/17; H10D62/351; H10D62/357; H10D62/364; H10D62/371; H10D84/817
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
213 words
A P channel high voltage transistor including: a P type semiconductor substrate, a first N type well region provided in the main surface of said P type semiconductor substrate, a first field oxide film provided in the main surface of said first N type well region, a P type source region and a P type drain region provided spaced apart from each other at the opposite sides of said first field oxide film in the main surface of said first N type well region, a P type impurity injection region provided immediately under said first field oxide film so as to be connected to said P type drain region and have a concentration lower than the impurity concentration of the P type drain region, a gate electrode provided between said P type source region and said P type drain region on said first N type well region, and an N + ion injection region provided in said N type well region under and separated from said P type source region and having a concentration higher than that of the N type impurities forming the N type well region, there being no N + ion injection region provided in said N type well region directly under said P type drain region at any depth.
Claim 2
Dependent Claim
213 words
A P channel high voltage transistor including: a P type semiconductor substrate, a first N type well region provided in the main surface of said P type semiconductor substrate, a first field oxide film provided in the main surface of said first N type well region, a P type source region and a P type drain region provided spaced apart from each other at the opposite sides of said first field oxide film in the main surface of said first N type well region, a P type impurity injection region provided immediately under said first field oxide film so as to be connected to said P type drain region and have a concentration lower than the impurity concentration of the P type drain region, a gate electrode provided between said P type source region and said P type drain region on said first N type well region, and an N + ion injection region provided in said N type well region under and separated from said P type source region and having a concentration higher than that of the N type impurities forming the N type well region, there being no N + ion injection region provided in said N type well region directly under said P type drain region at any depth.
Claim 3
Dependent Claim
188 words
The transistor according to claim 1, further including: a second N type well region provided spaced apart from said first N type well region in the main surface of said P type semiconductor substrate, a second field oxide film provided in the main surface of said second N type well region, an output side P + region and a V EE power source side P + region provided spaced from each other on the opposite sides of said second field oxide film in the main surface of said second N type well region, a P type impurity resistive layer provided immediately under said second field oxide film so as to connect said output side P + region and said V EE power source side P + region and having a concentration lower than that of the P type impurities forming these P + regions, and an electrode provided on said second field oxide film, said second N type well region located under said output side P + region and said V EE power source side P + region having its N type impurity concentration uniform at any depth.
Claim 4
Dependent Claim
34 words
The transistor according to claim 1, wherein said P type impurity injection region extends to a part immediately under bird's beak formation on said P type source region side of said field oxide film.
References Cited (Backward Citations)
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