Hynix Semiconductor Inc.

Hyundai Electronics Industries Co. Ltd.

Lg Semicon Co., Ltd.

Jong-Kwan Kim

Chang-Jae Lee

A method of fabricating a semiconductor device includes the steps of: forming a well of first conductivity type and well of second conductivity type in a substrate; forming a field oxide layer and gate oxide layer on the substrate; forming first and second polysilicon layers on the field oxide layer and gate oxide layer, the first polysilicon layer being doped with impurities of second conductivity type, the second polysilicon layer being doped with impurities of first conductivity, the first and second polysilicon layers coming into contact with each other; patterning the first and second polysilicon layers to be isolated from each other, to thereby forming first and second gates; and forming a conductive layer between the first and second gates. Accordingly, isolation of N-type and P-type polysilicon layers from each other, and patterning of them for the purpose of forming a gate are carried out using one mask, effectively simplifying the etching process during a gate patterning process. Also, by providing a conductive layer between the first and second gates, which electrically connects those gates, mutual diffusion of the impurities doping the polysilicon layers is prevented.

Method of fabricating semiconductor device

A method of forming a twin well includes the steps of: forming a field oxide layer on a semiconductor substrate to define active regions of a device, and forming a first mask which exposes a predetermined active region of the semiconductor substrate; ion-implanting a first conductivity type impurity into the exposed region of the semiconductor substrate using the first mask as an ion implantation mask, to form a first well; ion-implanting a second conductivity type impurity to penetrate the first mask, to form a buried region which is self-aligned with the first well and comes into contact with the bottom of the field oxide layer; removing the first mask, and forming a second mask which is to expose the first well of the semiconductor substrate; and ion-implanting a second conductivity impurity into the exposed region of the semiconductor substrate to levels deeper and shallower than the buried region using the second mask as an ion implantation mask, to form a second well including the buried region. The second well self-aligned with the first well. Damages due to ion implantation is not generated, preventing leakage current at the contact surface between the first well and semiconductor substrate. The surface impurity concentration of the second well is easily controlled, improving reproducibility.

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Chungcheongbuk-do, South Korea

Jong-Kwan Kim