Semiconductor device and method of manufacturing it
AssigneeSanyo Electric Co., Ltd.
InventorsShuichi Kikuchi, Eiji Nishibe
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Abstract
To enable the reduction of ON-state resistance in a state in which the withstand voltage is secured, a semiconductor device according to the invention is provided with a gate electrode formed so that the gate electrode ranges from a gate oxide film formed on an N-type well region formed in a P-type semiconductor substrate to a selective oxide film, a P-type source region formed so that the source region is adjacent to the gate electrode, a P-type drain region formed in a position apart from the gate electrode and a P-type drift region (an LP layer) formed so that the drift region surrounds the drain region, and is characterized in that a P-type impurities layer (an FP layer) is formed so that the impurities layer is adjacent to the drain region.
Claims13
A semiconductor device provided with a gate electrode formed so that the gate electrode ranges from a first gate oxide film formed on a first conductive type of semiconductor layer to a second gate oxide film, a second conductive type of source region formed so that the source region is adjacent to the gate electrode, a second conductive type of drain region formed in a position apart from the gate electrode and a second conductive type of drift region formed so that the drift region surrounds the drain region, wherein:
- a second conductive type of impurities layer is formed so that it is adjacent to the drain region.
A method of manufacturing a semiconductor device, comprising:
- a process for forming a second conductive type of layer by applying impurities of a second conductive type into/in a first conductive type of semiconductor layer;
- a process for forming an oxidation-resistant film in a predetermined region on the semiconductor layer;
- a process for forming a resist film in a predetermined region on the semiconductor layer including the oxidation-resistant film;
- a process for forming an ion implanted layer in a predetermined region on the semiconductor layer by implanting impurities of a second conductive type using the oxidation-resistant film and the resist film as a mask;
- a process for forming a selective oxide film by locally oxidizing the semiconductor layer using the oxidation-resistant film as a mask after the resist film is removed and forming a second conductive type of impurities layer by diffusing the ion implanted layer;
- a process for forming a gate oxide film by thermally oxidizing the semiconductor layer using the selective oxide film as a mask;
- a process for forming a gate electrode so that the gate electrode ranges from the gate oxide film to the selective oxide film;
- and
- a process for forming a second conductive type of source region so that the source region is adjacent to the gate electrode by implanting impurities of a second conductive type using the gate electrode and the selective oxide film as a mask and forming a second conductive type of drain region in a position apart from the gate electrode.
A semiconductor device comprising a gate electrode formed on a semiconductor layer of a first conduction type through a gate oxide film, a highly doped source region of a second conduction type formed to be adjacent to the gate electrode, a highly doped drain region of the second conduction type formed at a position apart from said gate electrode and a drift region of the second conduction type formed so as to surround said drain region,
- wherein an impurity region of the second conduction type which is more lightly doped than said highly doped drain region and is more highly doped than said drift region is formed so as to surround the vicinity of said highly doped drain region.
Dependencies are inferred from the claim text.