Sanyo Electric Co., Ltd.

Izuo Iida

Yuji Tsukada

Tatsuya Fujishima

Mikio Fukuda

Keiji Ogata

The invention is to prevent dielectric breakdown of a capacitor in a semiconductor device having the capacitor and a MOS transistor formed on a same semiconductor substrate. A SiOfilm that is to be a gate insulation film of a high voltage MOS transistor is formed on a whole surface of a P-type semiconductor substrate. A photoresist layer is selectively formed in a high voltage MOS transistor formation region and on a part of a SiOfilm covering edges of trench isolation films adjacent to a capacitor formation region, and the SiOfilm is removed by etching using this photoresist layer as a mask. Since the photoresist layer functions as a mask in this etching, the edges of the trench isolation films adjacent to the capacitor are not cut too deep. The SiOfilm remaining in this etching and a SiOfilm to be formed thereafter form a capacitor insulation film.

Method of manufacturing semiconductor device with capacitor and transistor

A memory transistor and a high breakdown voltage MOS transistor are easily formed on the same semiconductor substrate without changing the operational characteristics of the memory transistor. The process of forming the tunnel insulation film of the memory transistor and the process of forming the gate insulation film of the MOS transistor are performed separately. Concretely, an insulation film to be a part of the tunnel insulation film and a silicon nitride film are formed on the whole surface, and then the silicon nitride film in a MOS transistor formation region is selectively removed using a photoresist layer. Then, the MOS transistor formation region is selectively oxidized using the remaining silicon nitride film as an anti-oxidation mask to form the gate insulation film of the MOS transistor having a selected thickness.

Semiconductor device manufacturing method

A non-volatile memory cell and a high voltage MOS transistor on the same semiconductor chip without changing the characteristic of the non-volatile memory cell. A gate insulating film of a MOS transistor is formed using the steps of forming an oxide filmformed on a floating gateof a split-gate type non-volatile memory cell and of forming a tunneling insulating filmformed on the floating gateand the oxide film. The gate insulating filmof the MOS transistor is formed by a stacked layer of the oxide filmand tunneling insulating film. Thus, the quantity of heat treatment in the entire production process undergoes no change, and the optimized characteristic of the non-volatile memory undergoes no change.

Growing community of inventors

Tochigi, Japan

Izuo Iida