EP0335750A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Vertical power mosfet having high withstand voltage and high switching speed
Assignee: NEC Corp
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Filing: 1989-04-03
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Granted: —
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Expires: 2009-04-03
Abstract
Abstract In a vertical field effect transistor including a source electrode and a gate on the front surface of a semiconductor substrate having one conductivity type and a drain electrode on the back surface of the substrate, the semiconductor device of the present invention has the structure wherein a connection region of one conductivity type positioned between two channel forming base regions of the opposite conductivity type is formed by a semiconductor layer having a higher impurity concentration than the drain region of the one conductivity type, and the surface portion of the connection region which is connected to the channel has a lower impurity concentration than the connection region.
Inventors
- 👤 Mitsuasa Takahashi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 04:39
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/64; H10D30/66; H10D62/00; H10D62/10; H10D62/124; H10D62/126; H10D62/127; H10D30/662; H10D62/13; H10D62/149; H10D62/151; H10D62/156; H10D62/157; H10D62/60
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
171 words
A semiconductor device comprising: a semiconductor layer of one conductivity type; a plurality of base regions of the other conductivity type formed on a main surface of said semiconductor layer; a plurality of source regions of said one conductivity type formed in said plurality of base regions; a plurality of gate electrodes formed at least on portions of said base regions, said portions being outside said source regions; a first semiconductor region of said one conductivity type having a higher impurity concentration than said semiconductor layer, said first semiconductor region being formed on said main surface of said semiconductor layer between said plurality of base regions; a second semiconductor region of said one conductivity type having a lower impurity concentration than said first semiconductor region, said second semiconductor region being formed on the surface of said first semiconductor region; a first electrode connected electrically and commonly to said plurality of source regions; and a second electrode electrically connected to a back surface of said semiconductor layer opposed to said main surface.
Claim 2
Dependent Claim
171 words
A semiconductor device comprising: a semiconductor layer of one conductivity type; a plurality of base regions of the other conductivity type formed on a main surface of said semiconductor layer; a plurality of source regions of said one conductivity type formed in said plurality of base regions; a plurality of gate electrodes formed at least on portions of said base regions, said portions being outside said source regions; a first semiconductor region of said one conductivity type having a higher impurity concentration than said semiconductor layer, said first semiconductor region being formed on said main surface of said semiconductor layer between said plurality of base regions; a second semiconductor region of said one conductivity type having a lower impurity concentration than said first semiconductor region, said second semiconductor region being formed on the surface of said first semiconductor region; a first electrode connected electrically and commonly to said plurality of source regions; and a second electrode electrically connected to a back surface of said semiconductor layer opposed to said main surface.
Claim 3
Dependent Claim
20 words
A semiconductor device as claimed in claim 1, wherein said gate electrode is formed also on said second semiconductor region.
Claim 4
Dependent Claim
19 words
A semiconductor device as claimed in claim 1, wherein said first semiconductor region is shallower than said base regions.
Claim 5
Dependent Claim
19 words
A semiconductor device as claimed in claim 1, wherein said first semiconductor region is deeper than said base regions.
Claim 6
Dependent Claim
20 words
A semiconductor device as claimed in claim 1, wherein said source regions and said base regions have an octagonal shape.
Claim 7
Dependent Claim
40 words
A semiconductor device as claimed in claim 1, wherein said second electrode is connected to said back surface of said semiconductor layer through another semiconductor layer having said one conductivity type and a higher impurity concentration than said semiconductor layer.
Claim 8
Dependent Claim
81 words
A semiconductor device as claimed in claim 2, wherein impurity concentration of said semiconductor layer is from 1 x 10¹⁴ cm⁻³ to 5 x 10¹⁶ cm⁻³, conductivity of said semiconductor layer being from 100 ohm-cm to 0.4 ohm-cm, conductivity of said first semiconductor region being from 1.5 times to 3 times as large as that of said semiconductor layer, and impurity concentration of said second semiconductor region being from one half to twice as large as that of said semiconductor layer.
Claim 9
Dependent Claim
46 words
A semiconductor device as claimed in claim 7, wherein conductivity of said first semiconductor region is twice as large as that of said semiconductor layer, impurity concentration of said second semiconductor region being from one half of to the same as that of said semiconductor layer.
Claim 10
Dependent Claim
29 words
A semiconductor device as claimed in claim 7, wherein depth of said second semiconductor region is from 0.1 µm to one half of that of said first semiconductor region.
Claim 11
Dependent Claim
158 words
A vertical MOSFET comprising: a drain region; a plurality of base regions formed on a first surface of said drain region; a plurality of source regions formed in said plurality of base regions, respectively; a gate electrode formed on said first surface between said source regions; a first semiconductor region formed on said first surface of said drain region between said base regions, said first semiconductor region having a higher impurity concentration than said drain region and the same conductivity type as that of said drain region; a second semiconductor region formed on said first surface of said first semiconductor region, said second semiconductor region having a lower impurity concentration than said first semiconductor region and the same conductivity type as that of said drain region; a source electrode connected electrically and commonly to said plurality of source regions; and a drain electrode connected electrically to a second surface of said drain region opposed to said first surface.
Claim 12
Dependent Claim
158 words
A vertical MOSFET comprising: a drain region; a plurality of base regions formed on a first surface of said drain region; a plurality of source regions formed in said plurality of base regions, respectively; a gate electrode formed on said first surface between said source regions; a first semiconductor region formed on said first surface of said drain region between said base regions, said first semiconductor region having a higher impurity concentration than said drain region and the same conductivity type as that of said drain region; a second semiconductor region formed on said first surface of said first semiconductor region, said second semiconductor region having a lower impurity concentration than said first semiconductor region and the same conductivity type as that of said drain region; a source electrode connected electrically and commonly to said plurality of source regions; and a drain electrode connected electrically to a second surface of said drain region opposed to said first surface.
Claim 13
Dependent Claim
20 words
A vertical MOSFET as claimed in claim 10, wherein said source regions and said base regions have an octagonal shape.
Claim 14
Dependent Claim
81 words
A vertical MOSFET as claimed in claim 10, wherein impurity concentration of said drain region is from 1 x 10¹⁴ cm⁻³ to 5 x 10¹⁶ cm⁻³, conductivity of said drain region being from 100 ohm-cm to 0.4 ohm-cm, conductivity of said first semiconductor region being from 1.5 times to 3 times as large as that of said drain region, and impurity concentration of said second semiconductor region being from one half to twice as large as that of said drain region.
Claim 15
Dependent Claim
46 words
A vertical MOSFET as claimed in claim 12, wherein conductivity of said first semiconductor region is twice as large as that of said drain region, impurity concentration of said second semiconductor region being from one half of to the same as that of said drain region.
References Cited (Backward Citations)
No citation records indexed.
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