Mitsubishi Denki Kabushiki Kaisha

Renesas Technology Corp.

Makoto Ooi

Kojiro Yuzuriha

Shinichi Kobayashi

Moriyoshi Nakashima

Jun Sumino

Hiromi Makimoto

The invention provides a semiconductor memory device having a trench part serving as an isolation area formed on semiconductor substrate, control gate used for controlling write-operation and read-operation formed orthogonally to the trench part, a source line of a first diffused layer formed on the surface of the trench part along one of the longitudinal sides of the control gate, and on the semiconductor substrate between the neighboring trench parts, silicide layer formed over the surface of the source line, and a drain of a second diffused layer formed between the trench parts in the other of the longitudinal sides.

Semiconductor memory device

A field oxide film which is fine and having smaller upheaval of a bird's head is formed, so as to improve electrical characteristic of a conductive layer formed with end portions positioned on the field oxide film. A planarizing silicon film is formed on a silicon nitride film and a thermal oxide film, so as to planarize a concave generated between the thermal oxide film and a silicon nitride film. The planarizing silicon film is thermally oxidized, so as to form a planarizing thermal oxide film integrated with the thermal oxide film. Thereafter, the planarizing thermal oxide film is etched back to form the field oxide film, and the silicon nitride film and a polycrystalline silicon film are removed. Thereafter, the conductive layer with end portions positioned on the field oxide film is formed.

Method of manufacturing semiconductor device

A p-type well and an n-type well surrounding the p-type well are formed in a p-type semiconductor substrate under a field insulating film. A polysilicon resistance film is formed on the field insulating film simultaneously with a floating gate formed in a memory cell region. A polycide conductive film is formed on a interlayer insulating film simultaneously with an auxiliary bit line formed in the memory cell region, and the polycide conductive film is connected to the resistance film by a contact formed in a via hole. A wiring line formed on an interlayer insulating film is connected to the polycide conductive film by a contact formed in a via hole penetrating the interlayer insulating film. The two via holes are formed at positions corresponding to regions in the p-type well. A negative voltage is applied to the wiring line, and the potential of a predetermined point on the resistance film is measured.

Growing community of inventors

Tokyo, Japan

Makoto Ooi