EP0024905A2
Expired / Lapsed
EP
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Insulated-gate field-effect transistor
Assignee: Zaidan Hojin Handotai Kenkyu Shinkokai
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Filing: 1980-08-22
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Granted: —
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Expires: 2000-08-22
Abstract
Abstract A semiconductor device having a source region (12), a drain region (13) and a channel region which are formed in a surface portion of a semiconductor substrate (11), and a gate (14) formed with a material having a relatively high built-in voltage relative to the source region. This semiconductor device may further include, in the semiconductor substrate to extend along the channel region, a highly-doped region (33) having a conductivity type opposite to that of the source region. This highly-closed region may have an impurity concentration gradient which is greater toward its portion facing the abovesaid surface of the substrate. This construction serves to prevent the loss of the memory due to current leakage during absence of a bias voltage which otherwise would develop in semiconductor devices having a short-channel and a thin gate oxide layer (15), and due to irradiation of alpha-particle onto the device.
Inventors
- 👤 Jun-Ichi Nishizawa
- 👤 Tadahiro Ohmi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 10:03
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/60; H10D64/66; H10D64/667; H10B; H10B12/00; H10B12/30; H10B12/31; H10D30/00; H10D30/202; H10D30/60; H10D62/00; H10D62/10; H10D62/17; H10D62/213; H10D62/221; H10D62/235; H10D62/314; H10D64/661; H10D64/665; H10W; H10W42/00; H10W42/20; H10W42/25
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
175 words
A semiconductor device formed with an insulation-gate field effect transistor having a semiconductor substrate (11), and having, closer to a surface of said substrate, a source semiconductor region (12) of one conductivity type and a low resistivity, a drain region (13) and a channel semiconductor region of the opposite conductivity type and a high resistivity defined between said source region and drain region, and having a gate electrode (14a) formed on a surface of said channel region via a gate insulator layer, characterized in that (a) at least a portion of said gate electrode contacting said gate insulator layer is formed with a material which has a relatively high built-in voltage relative to said source region (12) and which is a metal, a metal silicide, or a highly -doped polysilicon of a conductivity type opposite to that of said source region; (b) an effective channel length of less than 1µm is defined by the distance between said source and said drain regions (12 and 13), and (c) said gate insulator layer is less than 500A.
Claim 2
Dependent Claim
175 words
A semiconductor device formed with an insulation-gate field effect transistor having a semiconductor substrate (11), and having, closer to a surface of said substrate, a source semiconductor region (12) of one conductivity type and a low resistivity, a drain region (13) and a channel semiconductor region of the opposite conductivity type and a high resistivity defined between said source region and drain region, and having a gate electrode (14a) formed on a surface of said channel region via a gate insulator layer, characterized in that (a) at least a portion of said gate electrode contacting said gate insulator layer is formed with a material which has a relatively high built-in voltage relative to said source region (12) and which is a metal, a metal silicide, or a highly -doped polysilicon of a conductivity type opposite to that of said source region; (b) an effective channel length of less than 1µm is defined by the distance between said source and said drain regions (12 and 13), and (c) said gate insulator layer is less than 500A.
Claim 3
Dependent Claim
48 words
A semiconductor device according to Claim 1, characterized in that it further comprises a semiconductor region of said opposite conductivity type having animpurity concentration higher than that of . said channel region provided beneath said channel region and extending at least a part of said effective channel length.
Claim 4
Dependent Claim
19 words
A semiconductor device according to Claim 1 or 2, characterized in that said metal is platinum, molybdenum or tungsten.
Claim 5
Dependent Claim
27 words
A semiconductor device according to Claim 1 or 2, characterized in that said metal silicide is molybdenum silicide, tungsten silicide, titanium silicide, tantalum silicide or platinum silicide.
Claim 6
Dependent Claim
20 words
A semiconductor device according to Claim 1, characterized in that said drain region (13) is formed with an inversion layer.
Claim 7
Dependent Claim
39 words
A semiconductor device according to Claim 1 or 2, characterized in that a highly doped buried region (33) having a conductivity type opposite to that of said source region is formed near said channel region in said semiconductor substrate.
Claim 8
Dependent Claim
20 words
A semiconductor device according to Claim 6, characterized in that said buried region (33)extends to contact said drain region (13).
Claim 9
Dependent Claim
21 words
A semiconductor device according to Claim 6, characterized in that said buried region (33) extends close to said drain region (13).
Claim 10
Dependent Claim
27 words
A semiconductor device according to Claim 6, characterized in that said buried region (33) extends to both of said drain region (13) and said source region (12).
Claim 11
Dependent Claim
88 words
A semiconductor device according to Claim 1, characterized in that (a) said semiconductor substrate (11) has a high impurity concentration and has a conductivity type opposite to that of said source region; (b) said semiconductor device further includes, at a surface of said substrate, a region of a lesser impurity concentration than that of said substrate and of a conductivity type same as that of said substrate, and (c)said source region, said drain region and said channel region are formed in said region of a lesser impurity concentration.
Claim 12
Dependent Claim
38 words
A semiconductor device according to Claim 6, characterized in that said buried region (33) has such an impurity concentration gradient that the degree of concentration is lower progressively toward the interior of said substrate from said surface thereof.
Claim 13
Dependent Claim
26 words
A semiconductor device according to Claim 1, or Claim 2, characterized in that said insulation-gate transistor constitutes a memory cell of a dynamic random access memory.
Claim 14
Dependent Claim
43 words
A semiconductor device according to Claim 12, characterized in that the electrode (32) is formed on the drain region (13) via a thin insulator layer (31) so that a storage capacitor is formed by this insulator layer, the drain region and the electrode.
Claim 15
Dependent Claim
22 words
A semiconductor device according to Claim 12, characterized in that a storage capacitor (C ) is formed in said drain region (13).
Claim 16
Dependent Claim
33 words
A semiconductor device according to Claim 13 or 14, characterized in that said source region (12) serves as a bit line (63), and said gate electrode (14a) serves as a word line (64).
Claim 17
Dependent Claim
25 words
A semiconductor device according to Claim 1 or 2, characterized in that said insulation-gate transistor serves as one of transistors constituting a complementary inverted circuit.
References Cited (Backward Citations)
No citation records indexed.
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