Hitachi, Ltd.

Ichiro Mitamura

Keiichi Higeta

Akihisa Uchida

Takeo Shiba

Noriyuki Sakuma

Katsumi Ogiue

Kunihiko Yamaguchi

Kiichiro Mukai

Yasushiro Nishioka

Hiroshi Shinriki

There is implemented memory cells and corresponding signal lines associated therewith in bipolar type static random access memories employing wirings of multi-layer construction for transmitting a common signal therethrough such as with respect to the individual word lines. The word lines implemented are formed from at least a pair of stacked conductive layers and which layers have interposed therebetween an insulating film. The pair of layers form a pair of wiring lines wherein together they form a work line and wherein the wiring lines are, furthermore, interconnected at predetermined intervals along the lengths thereof. This leads to the ability to decrease the chip size of semiconductor integrated circuits noting that a decrease in the voltage drop of a signal line results, and to prevent electromigration in the signal (wiring) lines. There is, furthermore, implemented a current line formed from a conductor layer which is extended along the direction of the word lines over a region, together with the word lines, where the memory cells are formed.

Bipolar SRAM having word lines as vertically stacked pairs of conductive

There is implemented memory cells and corresponding signal lines associated therewith in bipolar type static random access memories employing wirings of multi-layer construction for transmitting a common signal therethrough such as with respect to the individual word lines. The word lines implemented are formed from at least a pair of stacked conductive layers of a material whose principal component is aluminum and which layers have interposed therebetween an insulating film. The pair of layers form a pair of wiring lines corresponding together to a word line and wherein the wiring lines are, furthermore, interconnected at predetermined intervals along the lengths thereof. This leads to the ability to decrease the chip size of semiconductor integrated circuits noting that a decrease in the voltage drop of a signal line results, and to prevent electromigration in the signal (wiring) lines.

Bipolar static RAM having two wiring lines for each word line

A semiconductor memory device is provided such as the type having flip-flop memory cells each including two bipolar transistors in cross connection with each other. In certain embodiments, at least a part of a Schottky barrier diode or capacitor in the memory cell is formed under a digit line. This memory device is greatly reduced in its required area, and the Schottky barrier diode and capacitor are negligibly influenced by the digit line. In other embodiments, it is arranged to provide different electrodes for the Schottky barrier diode and the capacitor to optimize construction in a minimized space.

Semiconductor memory device

Growing community of inventors

Ohme, Japan

Ichiro Mitamura