Patent US5383708A successfully refreshed from Google Patents.
EP0287031A2
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High breakdown voltage insulating film provided between polysilicon layers
Assignee: Toshiba Corp
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Filing: 1988-04-12
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Granted: —
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Expires: 2008-04-12
Abstract
Abstract A poly-Si film (53, 54, 55) is formed on a first insulating film (52) overlying a semiconductor substrate (51). A second insulating film (56) is formed on the poly-Si film (53, 54, 55). The poly-Si film (53, 54, 55) comprises a layered structure of a non-single crystal silicon film (53) having a phosphorus concentration of less than 5 × 10²⁰ cm⁻³ or containing no phosphor, a poly-Si film (54) having a phosphorus concentration of over 5 × 10²⁰ cm⁻³ and a poly-Si film (55) containing a phosphorus concentration of over 5 × 10²⁰ cm⁻³ or containing no phosphorus. Since non-single crystal silicon film (53) adjacent to the first insulating film (52) and poly-Si film (55) adjacent to the second insulating film (56) are made lower in their phosphorus concentration, the phosphorus in the films (53) and (55) are not diffused toward the insulating films (53) and (56), respectively. It is thus possible to improve the breakdown voltage across the first and second insulating films.
Inventors
- 👤 Yuuichi C/O Patent Division Mikata
- 👤 Katsunori Ishihara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 09:29
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/60; H10D64/01; H10D64/031; H10D64/035; H10D64/66; H10D64/661; H10D64/662
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
101 words
In a semiconductor device having a poly-Si layer on a first insulating film overlying a semiconductor substrate and a second insulating film on said poly-Si film, said semiconductor device characterized in: that a poly-Si layer (52, 53, 54) is formed on the first insulating film and has an impurity of a second conductivity type, the upper and lower surface portions of the poly-Si layer contain no impurity or contain an impurity concentration whose level is lower than that at the rest of the poly-Si layer; and that a second insulating film (56) is formed on said poly-Si layer (52, 53, 54).
Claim 2
Dependent Claim
101 words
In a semiconductor device having a poly-Si layer on a first insulating film overlying a semiconductor substrate and a second insulating film on said poly-Si film, said semiconductor device characterized in: that a poly-Si layer (52, 53, 54) is formed on the first insulating film and has an impurity of a second conductivity type, the upper and lower surface portions of the poly-Si layer contain no impurity or contain an impurity concentration whose level is lower than that at the rest of the poly-Si layer; and that a second insulating film (56) is formed on said poly-Si layer (52, 53, 54).
Claim 3
Dependent Claim
50 words
A semiconductor device according to claim 1, characterized in that the lower surface portion of said poly-Si layer (52, 53, 54) is formed as a non-single crystal silicon film (53) containing an impurity concentration of less than 5 × 10²⁰ cm⁻³ as said second conductivity type or containing no impurity.
Claim 4
Dependent Claim
47 words
A semiconductor device according to claim 1, characterized in that the upper surface portion of said poly-Si layer (53, 54, 55) is formed as a poly-Si film (55) containing an impurity of less than 5 × 10²⁰ cm⁻³ as said second conductivity type or containing no impurity.
Claim 5
Dependent Claim
50 words
A semiconductor device according to claim 2, characterized in that said poly-Si layer (53, 54, 55) is a poly-Si film (54) containing an impurity of over 5 × 10²⁰ cm⁻³ as an impurity of a second conductivity type at an area other than said upper and lower surface portions thereof.
Claim 6
Dependent Claim
19 words
A semiconductor device according to claim 2, characterized in that said impurity of said second conductivity type is phosphorus.
Claim 7
Dependent Claim
19 words
A semiconductor device according to claim 3, characterized in that said impurity of said second conductivity type is phosphorus.
Claim 8
Dependent Claim
19 words
A semiconductor device according to claim 4, characterized in that said impurity of a second conductivity type is phosphorus.
Claim 9
Dependent Claim
20 words
A semiconductor device according to claim 1, characterized in that said first insulating film (52) is a thermal oxide film.
Claim 10
Dependent Claim
20 words
A semiconductor device according to claim 2, characterized in that said second insulating film (56) is a thermal oxide film.
Claim 11
Independent Claim
117 words
A method for manufacturing a semiconductor device which includes forming a poly-Si layer on a first insulating film overlying a semiconductor substrate of a first conductivity type and forming a second insulating film on the poly-Si film, said method characterized by the steps of: forming a first insulating film (52) on a major surface of a semiconductor surface of a first conductivity type; and forming, on the first insulating film, a poly-Si layer (53, 54, 55) having an impurity of a second conductivity type, characterized in that the upper and lower surface portions of said poly-Si layer contain no impurity or contain an impurity whose level is lower than that at the rest of the poly-Si layer.
Claim 12
Independent Claim
117 words
A method for manufacturing a semiconductor device which includes forming a poly-Si layer on a first insulating film overlying a semiconductor substrate of a first conductivity type and forming a second insulating film on the poly-Si film, said method characterized by the steps of: forming a first insulating film (52) on a major surface of a semiconductor surface of a first conductivity type; and forming, on the first insulating film, a poly-Si layer (53, 54, 55) having an impurity of a second conductivity type, characterized in that the upper and lower surface portions of said poly-Si layer contain no impurity or contain an impurity whose level is lower than that at the rest of the poly-Si layer.
Claim 13
Dependent Claim
77 words
A method according to claim 10, characterized in that said lower surface portion of said poly-Si layer (53, 54, 55) is a non-single crystal silicon layer (53) having a phosphorus concentration of less than 5 × 10²⁰ cm⁻³ as an impurity of said second conductivity type, said poly-Si layer having a phosphorus concentration of less than 5 × 10²⁰ cm⁻³ and being formed by LPCVD method in a thermally decomposed silane/phosphine gaseous atmosphere at 400°C to 600°C.
Claim 14
Dependent Claim
63 words
A method according to claim 10, characterized in that said upper surface portion of said poly-Si layer (53, 54, 55) is a poly-Si film (55) having a phosphorus concentration of less than 5 × 10²⁰ cm⁻³ as an impurity of said second conductivity type, said poly-Si film being formed by LPCVD method in a thermally decomposed silane/phosphine gaseous atmosphere at 400°C to 800°C.
Claim 15
Dependent Claim
69 words
A method according to claim 10, characterized in that an area of said poly-Si layer (53, 54, 55) other than said upper and lower surface areas thereof constitutes a poly-Si film (54) having a phosphorus concentration of over 5 × 10²⁰ cm⁻³ as an impurity of said second conductivity type, said poly-Si film being formed by LPCVD method in a thermally decomposed gaseous silane/phosphine atmosphere at 600°C to 800°C.
Claim 16
Dependent Claim
33 words
A method according to claim 10, characterized in that said second insulating film (56) is a thermal oxide film obtained by thermally oxidizing the surface portion of said poly-Si layer (53, 54, 55).
References Cited (Backward Citations)
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