Hitachi, Ltd.

Atsuo Hotta

Yukio Kato

Teruo Isobe

Masahiro Iwamura

Hideo Maejima

Hiroyuki Kondo

Michio Suzuki

Kozaburo Kurita

Tetsuo Nakano

Akio Hayasaka

In a semiconductor integrated circuit, drain-source paths of an NMOS transistor and a PMOS transistor are connected between the base and emitter of a bipolar transistor, and control signals are applied to gates of the NMOS transistor and the PMOS transistor so as to keep the NMOS transistor and the PMOS transistor at OFF condition when the bipolar transistor is operating and so as to keep the NMOS transistor and the PMOS transistor at ON condition when the bipolar transistor is in the quiescent state.

Tristate circuit using bipolar transistor and CMOS transistor

Disclosed is a memory cell circuit including a pair of memory transistors having respective collectors and bases cross-coupled to each other, wherein load means connected to the collector of each one of said memory transistors comprises a parallel circuit of a load resistance and a transistor whose emitter and collector are connected to both ends of the load resistance and whose base is connected to the collector of the other of the memory transistors, thereby causing the readout currents of the memory cell circuit to be greater irrespective of increased load resistances.

Emitter coupled flip flop memory with complementary bipolar loads

A bipolar memory circuit is provided with a delay circuit which receives a write enabling signal, a gate circuit which detects the coincidence between an input signal and an output signal of the delay circuit, and a circuit which is started by an output signal of the gate circuit and which provides a pulse signal of a fixed time. The operation of a write driver circuit in the bipolar memory circuit is controlled by the pulse signal. Noise interfering in the write enabling signal are neglected by the use of the delay circuit and the gate circuit. The pulse width of the write enabling signal is permitted to be made smaller than the pulse width of the pulse signal required by the write driver circuit.

Bipolar memory circuit

The invention relates to an improvement in a semiconductor memory device including flip-flop type memory cells, each memory cell consisting of a pair of cross-coupled multi-emitter transistors. The semiconductor memory device of the invention is characterized by including a capacitance added between the collector region and the base region of each of the transistor pair of each memory cell in order to prevent the memory cell from erroneously operating due to .alpha.-rays.

Semiconductor memory device

An emitter junction type bipolar memory cell circuit having clamp diodes connected in parallel to collector resistances. The collector resistances are set to produce a potential difference of greater than 0.6 V or so caused by the stationary current. By so doing, it is possible to exclude any mal-function attributable to noises in the writing operation of the memory circuit.

In an oxide film isolation process wherein a groove portion is formed in that region of a semiconductor substrate in which an isolation layer is to be formed, oxygen or nitrogen is implanted into the groove portion by ion implantation so as to form an insulating layer beneath the groove portion, and the groove portion is thereafter oxidized to thus form an oxide of the semiconductor substrate in a manner to join the oxide and the insulating layer, whereby the area in a semiconductor chip surface as occupied by the isolation layer can be made small to enhance the density of integration of an integrated circuit.

Oxide film isolation process

A method of manufacturing bipolar transistor elements in a semiconductor integrated circuit isolated by a silicon oxide film, comprises the steps of forming a semiconductor layer of one conductivity type on a semiconductor substrate of the opposite conductivity type, in which each collector region of the one conductivity type is formed, diffusing an impurity of the opposite conductivity type for each base region into the surface of the semiconductor layer of the one conductivity type, performing oxidation down to the surface of the semiconductor substrate by employing an oxidation-resisting film as a mask, to thereby form an isolating silicon oxide film, and diffusing an impurity of the one conductivity type for each emitter region into a selected part of the surface of the diffused semiconductor layer of the opposite conductivity type, whereby the base width of the bipolar transistor elements can be narrowed.

Growing community of inventors

Higashiyamato, Japan

Atsuo Hotta