Renesas Technology Corp.

Keiichi Haraguchi

Kenji Kanamitsu

Masataka Kato

Tetsuo Adachi

Shoji Shukuri

Daisuke Okada

Tsutomu Okazaki

Yoshihiro Ikeda

Tatsuya Fukumura

Koji Kishi

Keisuke Tsukamoto

Naohiro Hosoda

Takashi Moriyama

A reduction in size nonvolatile semiconductors for use in a memory device and an increase in the capacity thereof are promoted. Each memory cell of a flash memory is provided with a field effect transistor having a first gate insulator film formed on a p-type well, a selector gate which is formed on the first insulator film and has side faces and a top face covered with a silicon oxide film (first insular film), floating gates which are formed in a side-wall form on both sides of the selector gate and which are electrically isolated from the selector gate through the silicon oxide film, a second gate insulator film formed to cover the silicon oxide film and the surface of each of the floating gates, and a control gate formed over the second gate insulator film.

Nonvolatile semiconductor memory device and a method of the same

An AND flash memory of the type wherein a memory cell is constituted of n-type semiconductor regions (a source and a drain) formed in a p-type well of a semiconductor substrate and three gates (including a floating gate, a control gate and a selective gate) is manufactured. In the manufacture, arsenic (As) is introduced into a p-type well in the vicinity of one of side walls of the selective gate to form n-type semiconductor regions (a source and a drain). Thereafter, to cope with a drain disturb problem, the substrate is thermally treated by use of an ISSG (In-Situ Steam Generation) oxidation method so that a first gate, insulating film disposed in the vicinity of one of side walls, at which the n-type semiconductor regions have been formed, is formed thick.

Method of manufacturing a nonvolatile semiconductor memory device

A non-volatile semiconductor memory device provides for higher integration by reducing the area of occupation of direct peripheral circuits, in which the memory cell of an AND type flash memory includes a selection gate, a float gate, a control gate that functions as a word line, and an n-type semiconductor region (source, drain) that functions as a local bit line. A pair of local bit lines adjacent to each other in a memory mat are connected with one global bit line at one end in the direction of the column of the memory mat, and a selection MOS transistor, formed by one enhancement type MOS transistor and one depletion type MOS transistor; is connected in series with each of the pair of local bit lines. One of the local bit lines is selected by turning the selection MOS transistor on/off.

Nonvolatile semiconductor memory device

At least not less than one capacitor formation trench providing an uneven surface is formed on the surface of a capacitor formation region. Thus, the surface area of a capacitor is increased, which enables improvement of the capacitance of the capacitor per unit area. Further, by forming the capacitor formation trench and an element formation trench that are formed in the surface of the semiconductor substrate by the same step, it is possible to simplify the manufacturing process. Whereas, a dielectric film of the capacitor in the capacitor formation region and a high-voltage gate insulating film in a MISFET formation region are formed by the same step; alternatively, the dielectric film of the capacitor in the capacitor formation region and a memory gate interlayer film between a polysilicon layer and a polysilicon layer in the memory cell formation region are formed by the same step.

Method of manufacturing a semiconductor device having trenches for isolation and capacitor formation trenches

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Hitachinaka, Japan

Keiichi Haraguchi