Semiconductor device and method for fabricating the same
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorHiroyuki Doi
Life of this patent
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Abstract
A constant voltage device includes n-type and p-type doped layers. The n-type doped layer is formed by heavily doping with an n-type impurity an upper portion of a p-type silicon semiconductor substrate, in an active region defined by an isolating insulator film. The p-type doped layer is formed by doping the region under the n-type doped layer with a p-type impurity. The n-type and p-type doped layers are provided to form two layers in parallel with the substrate surface of the semiconductor substrate, whereby a pn junction formed between the n-type and p-type doped layers creates a diode structure. Impurity concentration in the p-type doped layer is established so that the impurity concentration of a portion adjacent the isolating insulator film is lower that that of the rest.
Claims26
A semiconductor device comprising:
- a first doped layer and a second doped layer.
A semiconductor device comprising:
- an active layer and
- an isolating insulator film directly connected to said active layer,
- said active layer including a high-concentration doped layer directly connected to a low-concentration doped layer having a conductivity type different than said high-concentration doped layer,
- wherein a first portion of said low-concentration doped layer adjacent said isolating insulator film has an ion concentration lower than another portion of said low-concentration doped layer.
A semiconductor device comprising:
- a first doped layer and
- a second doped layer.
A semiconductor device comprising:
- a high-concentration doped layer,
- a low-concentration doped layer having a conductivity type different than said high-concentration doped layer, and
- an isolating insulator film,
- wherein said high-concentration doped layer is directly connected to said low-concentration doped layer and not directly connected to said isolating insulator film.
A method for manufacturing a semiconductor device comprising the steps of:
- forming an isolating insulator film in a semiconductor substrate so that said isolating insulator film is connected to an active region,
- forming a high-concentration doped layer in the active region, and
- forming a low-concentration doped layer having a conductivity type different than said high-concentration doped layer so that said low-concentration doped layer is connected to said high-concentration doped layer in the active region,
- wherein the step of forming a low-concentration doped layer includes forming a first portion of said low-concentration doped layer adjacent said isolating insulator film, the first portion having an ion concentration lower than another portion of said low-concentration doped layer.
A method for manufacturing a semiconductor device comprising the steps of:
- forming an isolating insulator film in a semiconductor substrate,
- forming a high-concentration doped layer in the semiconductor substrate in such a manner that said high-concentration doped layer is not directly connected to said isolating insulator film, and
- forming a low-concentration doped layer having a conductivity type different than said high-concentration doped layer in the semiconductor substrate so that low-concentration doped layer is directly connected to said high-concentration doped layer.
Dependencies are inferred from the claim text.