SEMICONDUCTOR DEVICE AND METHOD OF MANUFACTURING THE SAME
First Claim
1. A semiconductor device including at least one of a first to a third types of transistors on a semiconductor substrate, a transistor of said first type comprises:
- a first semiconductor layer of a first conductivity type which is formed in a surface of said semiconductor substrate;
a first channel dope layer of the first conductivity type which is formed selectively in said first semiconductor layer; and
a first control electrode which is formed at a position which faces said first channel dope layer, on said first semiconductor layer, a transistor of said second type comprises;
a second semiconductor layer of the first conductivity type which is formed in the surface of said semiconductor substrate;
a second channel dope layer of the first conductivity type which is formed selectively in said second semiconductor layer; and
a second control electrode which is formed at a position which faces said second channel dope layer, on said second semiconductor layer, a transistor of said third type comprises;
a third semiconductor layer of the first conductivity type which is formed in the surface of said semiconductor substrate;
a third channel dope layer of the first conductivity type which is formed selectively in said third semiconductor layer; and
a third control electrode which ss formed at a position which faces said third channel dope layer, on said third semiconductor layer, and at least one of said first to said third control electrodes internally includes an impurity layer of the second conductivity type having a concentration distribution in the direction of depth.
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Accused Products
Abstract
According to a semiconductor device and a method of manufacturing the same, a trade-off relationship between threshold values and a diffusion layer leak is eliminated and it is not necessary to form gate oxide films at more than one stages. Since impurity dose are different from each other between gate electrodes (4A to 4C) of N-channel type MOS transistors (T41 to T43), impurity concentration in the gate electrodes (4A to 4C) are different from each other. The impurity concentration in the gate electrodes are progressively lower in the order of higher threshold values which are expected.
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Citations
16 Claims
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1. A semiconductor device including at least one of a first to a third types of transistors on a semiconductor substrate,
a transistor of said first type comprises: -
a first semiconductor layer of a first conductivity type which is formed in a surface of said semiconductor substrate;
a first channel dope layer of the first conductivity type which is formed selectively in said first semiconductor layer; and
a first control electrode which is formed at a position which faces said first channel dope layer, on said first semiconductor layer, a transistor of said second type comprises;
a second semiconductor layer of the first conductivity type which is formed in the surface of said semiconductor substrate;
a second channel dope layer of the first conductivity type which is formed selectively in said second semiconductor layer; and
a second control electrode which is formed at a position which faces said second channel dope layer, on said second semiconductor layer, a transistor of said third type comprises;
a third semiconductor layer of the first conductivity type which is formed in the surface of said semiconductor substrate;
a third channel dope layer of the first conductivity type which is formed selectively in said third semiconductor layer; and
a third control electrode which ss formed at a position which faces said third channel dope layer, on said third semiconductor layer, and at least one of said first to said third control electrodes internally includes an impurity layer of the second conductivity type having a concentration distribution in the direction of depth. - View Dependent Claims (2, 3, 4, 5)
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6. A method of manufacturing a semiconductor device in which there are at least one of a first to a third types of transistors on a semiconductor substrate, comprising the steps of:
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(a) forming a first to a third semiconductor layers of the first conductivity type at positions within a surface of said semiconductor substrate at which said first to said third types of transistors are formed;
(b) selectively forming a first, a second and a third channel dope layers of the first conductivity type within said first, said second and said third semiconductor layers, respectively, by ion implantation; and
(c) forming a first to a third control electrodes at positions facing said first to said third channel dope layers on said first to said third semiconductor layers, wherein said step (c) of forming said first to said third control electrodes includes a step of forming an impurity layer of the first conductivity type which has a concentration distribution in the direction of depth within at least one of said first to said third control electrodes. - View Dependent Claims (7, 8, 9, 10, 11, 13, 14, 15, 16)
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12. A method of manufacturing a semiconductor device in which there are a first and a second types of transistors formed on a single semiconductor substrate, comprising the steps of:
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(a) selectively forming a field oxide film on a main surface of said semiconductor substrate to thereby define a first and a second regions in which said first and said second types of transistors are formed;
(b) forming an oxide film on said first and said second regions and over said field oxide film;
(c) forming a conductive layer, which becomes a control electrode, on said oxide film; and
(d) introducing an impurity of the same conductivity type as that of a source/drain layer into said conductive layer on at least one of said first and said second regions.
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Specification