Matsushita Electronics Corporation

Matsushita Electronics Company

Kyoko Miyamoto

Fumihiko Noro

Hideaki Onishi

Kazuo Sato

Kazuya Kubo

Kenji Ueda

Kazuo Umeda

Michio Morita

Satoshi Nakagawa

A floating gate type semiconductor memory and method of manufacture are described including an erasing gate electrode in which a tunneling region can be formed easily and high reliability can be kept. An active region isolated by element isolation insulating films is formed on a semiconductor substrate. A gate insulating film and a floating gate electrode are sequentially formed on the active region. A control gate electrode is formed above the floating gate electrode with a silicon oxide film disposed therebetween. A tunneling insulating film is formed only on the side wall of the floating gate electrode. Then, an erasing gate electrode is formed so as to cover the tunneling insulating film.

Method for forming semiconductor memory device

A highly reliable semiconductor IC circuit can be produced by this etching method: A resist layer is formed on a polysilicon layer which is formed on a silicon dioxide layer on a silicon substrate. The resist layer is used as a mask, and silicon oxide layer deposits thereon while polysilicon layer is being etched. Carbon emission out of the resist layer is thus restrained, and thereby a selectivity, an etching speed ratio of polysilicon layer vs. silicon dioxide layer, is substantially raised.

Method of etching polysilicon layer

A floating gate type semiconductor memory and method of manufacture are described including an erasing gate electrode in which a tunneling region can be formed easily and high reliability can be kept. An active region isolated by element isolation insulating films is formed on a semiconductor substrate. A gate insulating film and a floating gate electrode are sequentially formed on the active region. A control gate electrode is formed above the floating gate electrode with a silicon oxide film disposed therebetween. A tunneling insulating firm is formed only on the side wall of the floating gate electrode. Then, an erasing gate electrode is formed so as to cover the tunneling insulating film.

Semiconductor memory having a tunneling region

The invention provides a process to form on a certain conductive type semiconductor substrate 1 insulation layer 9 having openings 11, which regions will become source and drain; a process to form diffusion layer 8 of the same conductive type as semiconductor substrate 1 in to-be-drain space, with insulation layer 9 and photoresist 10 as masks; a process to form side wall layer 13 alongside openings of insulation layer 9; a process to form diffusion layers 4 and 5, conductive type of which layers is opposite to that of semiconductor substrate 1, in to-be-source and to-be-drain regions, with insulation layer 9 and side wall layer 13 as masks; a process to remove insulation layer 9 and side wall layer 13; and a process to form insulation layer 2 on semiconductor substrate in channel region distinguished by, and including part of, diffusion layers 4 and 5, and to form floating-gate electrode 3 on insulation layer 2, and control-gate electrode 7 with insulation layer 6 in between. The manufacturing method according to this invention forms drain and high density P-type diffusion layer by making use of side wall layer. Therefore, this makes it possible to shape DSA structure controlling the distance from drain to high density P-type diffusion layer with high accuracy, without using high temperature diffusion process. This means that this invention offers an easy way to make DSA structure with finer design rules.

Growing community of inventors

Kyoto, Japan

Kyoko Miyamoto