Mitsubishi Denki Kabushiki Kaisha

Yoshio Kohno

Hirotada Kuriyama

Shinichi Satoh

Hidekazu Oda

Masahiro Yoneda

Koichi Moriizumi

Masahiro Hatanaka

Teruhiko Okada

Yukio Maki

Junichi Mitsuhashi

Hideki Genjyo

A semiconductor device is an SRAM cell having a pair of access transistors, a pair of driver transistors and a pair of load transistors. A gate electrode of the load transistor is electrically connected to a region of a semiconductor substrate which is surrounded by a gate electrode of the driver transistor, a channel region of the load transistor is formed opposite to the gate electrode of the load transistor with an insulating film therebetween, and a pair of source/drain regions of the load transistor are formed to sandwich the channel region.

Semiconductor device

A semiconductor device includes a gate electrode, and a semiconductor layer formed on the main surface of the gate electrode with a gate oxide film therebetween. The semiconductor layer has a channel region opposing the main surface of gate electrode and source/drain regions having the channel region therebetween, and is formed so that the bent angle in the vicinity of the boundaries of the channel region and the source/drain regions is beyond 90.degree.. Thus, the semiconductor layer formed in a thin film transistor has no orthogonal bent, and, therefore the concentration of electric fields is suppressed, improving the performance of the thin film transistor.

Semiconductor device and manufacturing method thereof

A memory cell array in a static random access memory (SRAM) includes an improved circuit. Memory cells in one row are connected to a ground line. The memory cells in another row are connected to the ground line. Word lines each are connected alternately to the memory cells of two rows column by column. In a read operation, when one of the word lines is activated, a current flows from the memory cell to the two ground lines. Since a total of currents flowing through one ground line is reduced, the rise of potentials of the ground lines is prevented, so that destruction of data can be prevented.

Semiconductor memory device including memory cells connected to a ground

The invention provides an SRAM memory cell structure permitting increase of integration density while maintaining operation stability. A memory cell in the SRAM includes a pair of access transistors, a pair of driver transistors, and a pair of load transistors. The gate insulating film of access transistor is formed of a single layer of silicon oxide film, while the gate insulating film of driver transistor is formed of a stacked layer formed of a silicon oxide film and a silicon nitride film. The pair of load transistors are formed of two layers of polycrystalline silicon layers stacked upon each other with an insulating film therebetween. A source region and a drain region are formed in each of polycrystalline silicon layers with each channel region therebetween. One drain region forms a gate opposite to the other channel region, while the other drain region forms a gate opposite to the one channel region.

SRAM memory structure and manufacturing method thereof

A high load resistance type static random access memory (SRAM) is provided, as an example of a semiconductor device having a high resistance layer. The SRAM includes a semiconductor substrate (1) of a first conductivity type with an impurity diffusion region (3) of second conductivity type selectively formed thereon. An aluminum interconnection layer (8) is formed over the impurity diffusion region (3). Provided between the aluminum interconnection layer (8) and the impurity diffusion region (3) is a double-layer high resistance structure which comprises a nitride layer (63a) formed adjacent the semiconductor substrate (1) and an oxide layer (63b) adjacent the aluminum interconnection layer (8). The impurity diffusion region (3) forms part of a MOS field effect transistor, which is coupled to the high resistance layer (63) to form a flip-flop memory cell. The double-layer high resistance structure makes it possible to adjust the resistance at a desired particular high value by controlling the thickness of the layer. The structure permits a high degree of integration of the SRAM. The high resistance layer is not affected by diffusion or penetration of the impurity thereto.

Semiconductor device having multiple layer resistance layer structure

A dynamic type semiconductor device comprises a memory cell array including a plurality of cell groups, each of the cell groups including four adjacent memory cells disposed in a point symmetry fashion, with a single contact hole formed at the center of the point symmetry to be common to the four memory cells, in which the four memory cells and bit lines are connected through the single contact hole.

Semiconductor memory cells having common contact hole

A semiconductor memory device comprises four memory cells (4a, 6) arranged in point symmetry on a semiconductor substrate (1), and an insulating layer (10) covering the memory cells and having one contact hole (2) placed in the center of the point symmetry, with the contact hole enabling electrical connection to each of the memory cells.

Growing community of inventors

Hyogo, Japan

Yoshio Kohno