Kabushiki Kaisha Toshiba

Yuuichiro Murahama

Hiroaki Tsunoda

Minori Kajimoto

Ryuichi Kamo

Riichiro Shirota

Seiichi Aritome

Yuji Takeuchi

Osamu Ikeda

Hitoshi Araki

Masamitsu Yahata

Masashi Umemura

A semiconductor device such as a flash memory includes a semiconductor substrate, two gate insulating films formed on the substrate so as to have a first film thickness and a second film thickness smaller than the first film thickness respectively, and a polycrystalline silicon film formed on the gate insulating films so that parts of the polycrystalline silicon film on the respective gate insulating films are on a level with each other and serving as a gate electrode. The substrate is formed with a recess defined by a bottom and sidewalls substantially perpendicular to the bottom, the recess corresponding to the part of the gate insulating film with the first film thickness.

Semiconductor device and method of fabricating the same

Semiconductor device and method for fabricating the same

In a semiconductor device of MOS structure, the element region has a shape such as a square shape which has a plurality of sides and a plurality of corners. On the element region, a conductive film which constitutes one electrode of the MOS structure is formed. The other electrode of the MOS structure is a silicon substrate. The conductive film is provided so as to cover at least sides adjacent to each other and so as not to cover the corners including the corners which are the contact points (intersecting points) of the adjacent sides. Further, in case the element region is in a ring shape, the conductive film is provided so as to cover none of the corners including the inside corners of the ring-shaped element region. By the above-mentioned structure, the occurrence of breakdown in the insulation film in the MOS structure can be prevented, and the reliability thereof can be enhanced.

Semiconductor device and semiconductor integrated circuit having a conductive film on element region

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Yokohama, Japan

Yuuichiro Murahama