Nec Corporation

Isami Sakai

Hiroshi Ito

Hiroshi Kawaguchi

Hitoshi Abiko

Kazuhiro Okabe

According to the present invention, there is disclosed a 2-transistors type flash memory, wherein a memory-transistor is composed of layers of structure consisting of a floating gate and a control gate separated by a first insulating film; and, at least, a gate electrode of a select-transistor is composed of a single layer of a polysilicon film, which is formed from the same layer as the floating gate electrode of the memory-transistor and then doped to have an enhanced dopant concentration by ion implantation performed in the step of forming source-drain regions of the transistors.

Method of manufacturing a flash memory having a select transistor

According to the present invention, there is disclosed a 2-transistors type flash memory, wherein a memory-transistor is composed of layers of structure consisting of a floating gate and a control gate separated by a first insulating film; and, at least, a gate electrode of a select-transistor is composed of a single layer of a polysilicon film, which is formed from the same layer as the floating gate electrode of the memory-transistor and then doped to have an enhanced dopant concentration by ion implantation performed in the step of forming source-drain regions of the transistors

A semiconductor device of the present invention and using trench isolation includes contact holes. Spacers are formed on the shoulder portions of a device region exposed in the contact holes. To form the spacers, a silicon oxide film is formed and then etched by anisotropic etching such that the film does not fill up the contact holes. The anisotropic etching may be effected after oxidation. With this structure, it is possible to prevent junction leakage current from increasing.

Semiconductor device and method of producing the same

A method for manufacturing an integrated circuit, wherein, before providing an IC composite by forming a metal film on an IC assembly which includes a semiconductor substrate and a silicon part formed along the substrate and consisting essentially of silicon, an amorphous region is formed into the silicon part. The IC composite is subjected to first primary and secondary heat treatments in a nitrogen atmosphere and then to a second heat treatment at 600.degree.-700.degree. C., 700.degree.-900.degree. C., and 700.degree.-900.degree. C. to turn the metal film on the silicon part into a metal silicide film of excellent uniformity. The assembly has a silicon dioxide portion, on which the metal film is turned during the first primary and secondary heat treatments into a metal nitride film. The second heat treatment is carried out after the removal of the metal nitride film.

Integrated circuit with a metal silicide film uniformly formed

The present invention provides an input protection circuit including a first MOS FET including a source electrically connected to an input terminal and a drain and a gate both electrically connected to a grounding line, a second MOS FET including a source electrically connected to the input terminal and a drain and a gate, and a third MOS FET including a source electrically connected to a power line and a drain and a gate to both of which are electrically connected a drain and a gate of the second MOS FET. The input protection circuit shares a parasitic p-MOS transistor with an internal circuit, and hence it is no longer necessary to form a parasitic MOS transistor to be used only for an input protection circuit. Thus, the input protection circuit decreases the number of photomask using steps by one relative to a conventional protection circuit. In addition, the sharing a parasitic MOS transistor with an internal circuit makes it possible to prevent a current from running from an input terminal to a power line, even if a voltage higher than a source voltage is input to the input terminal. Thus, it is possible to enhance resistance to electrostatic breakdown, and fabricate an integrated circuit having high reliability with lower cost.

Input protection circuit and method of fabricating semiconductor

In a method for forming silicide films on a silicon substrate being formed thereon with a gate surrounded by gate side walls and being formed therein with diffusion regions, the silicide film being formed on a predetermined region of the silicon substrate at least except for an extremely thin film on the gate side walls. The method comprises the following steps. The silicon substrate is subjected to a collimated sputtering of metal atoms with use of a meshed mask on the silicon substrate surface to deposit a metal film on an entire surface of the silicon substrate, except for an extremely thin film on the vertical walls. The deposited metal film is further subjected to a heat treatment to react the metal film with the diffusion regions to thereby selectively form a metal silicide film at least on the diffusion regions, except for an extremely thin film on the vertical walls.

Method for selective formation of silicide films without formation on

A composite semiconductor integrated circuit device includes logic circuit blocks of a master slice system and function blocks such as memories all of which are integrated on a single semiconductor chip. The function blocks are constituted with n lower metal wiring layers. On a portion of a surface of the chip which overlaps with the function block, a (n+1)th metal layer is not provided as signal wiring, but a (n+2)th metal wiring layer or higher layers are provided. The step coverage of the metal wiring layers provided on the chip surface portion overlapping with the function block is improved and cross-talk between signal lines can be reduced.

Composite semiconductor integrated circuit device

An integrated circuit chip includes a substrate in which active circuits are formed, a lower layer of parallel conductors formed on the substrate, and one or more intermediate layers of insulating material on the lower-layer conductors, the intermediate layers having troughs corresponding to spaces where the lower-layer conductors are absent on the substrate and crests corresponding to spaces where the lower-layer conductors are present on the substrate. An upper layer of parallel conductors is formed on the insulative layers, the upper-layer conductors extending in a direction normal to the length of the lower-layer conductors. The upper-layer conductors have a minimum step coverage of 50%, and the lower-layer conductors have a ratio of a thickness thereof to a separation therebetween, which ratio is either equal to or greater than 0.45 or equal to or smaller than 0.25.

Multilayered integrated circuit chip wiring arrangement

Disclosed is an improved metal oxide-semiconductor field-effect transistor having two diffused regions extending apart from under one and the other edge of the gate in the opposite directions, at least one of the diffused regions being composed of a first leastdoped, short section, a second lightly-doped, short section, and a third heavily-doped, long section. Either diffused region may be used as drain. The series-connection of least and lightly-doped sections of the same longitudinal size or depth improves the current driving capability of the semiconductor device. Also, methods of making such MOSFETs are disclosed.

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Tokyo, Japan

Isami Sakai