Kabushiki Kaisha Toshiba

Yasumitsu Nozawa

Masami Masuda

Takayuki Kawaguchi

Makoto Segawa

Shigeto Mizukami

Takayuki Otani

Kenichi Nakamura

Satoru Hoshi

Yoichi Suzuki

Akihiro Mishima

Kouji Nakao

A semiconductor memory device includes bit lines and word lines arranged lengthwise and breadthwise, memory cells 1 capable of reading out and writing in, MOS transistors Q1 and Q2 for pre-charge, MOS transistors Q3 for short-circuiting, and transistors Q4 and Q5 for setting voltage level. The bit lines are provided two pieces at each bit. Between the MOS transistors Q1, Q2 for pre-charge and the bit lines driving power supply terminal Vcc, three pieces of the fuses F1-F3 are connected at each column. When the leak defect occurs to the bit lines, all of the fuses F1-F3 connected to the bit lines are cut. Further, a semiconductor memory device includes a plurality of section regions, a redundancy circuit RD1 which replaces a defective cell at each section region, a redundancy circuit RD2 which replaces the defective cell at each row address. The section regions are provided at each address in the column direction. In each section region, cell ground power supply lines Vss are formed circularly. Outside each section region a pad ground power supply line Vss' are formed. Each of the cell ground power supply lines Vss and the pad ground power supply line Vss' are connected via a plurality of fuses F connected in parallel.

Semiconductor memory device and method relieving defect of semiconductor

A semiconductor memory device includes normal row selection lines (NWL1 to NWL128) for selecting one of normal rows, a spare row selection line (SWL) for selecting a spare row instead when one of the normal rows has a defect, fuses (F1 to F128) which are respectively arranged on the normal row selection lines, and blown when a defect exists, a normal row non-selection circuit (inverters IN3 and IN6 and gate G3) when one of the fuses (F1 to F128) is blown, setting a corresponding normal row in a non-selected state, and a spare row selection circuit (gates G4, G5, and G6, transistors P2 and N1, a NOR gate NR1, and an inverter IN6) selecting the spare row instead of the defective normal row. The spare row selection circuit performs dynamic operation in synchronism with a clock (ck). In this manner, control of, when a defect exists in a normal row or column, switching the defective row or column to a spare row or column is performed by dynamic operation in synchronism with an internal clock, thereby increasing the access speed.

Semiconductor memory device

A semiconductor device comprises: a first circuit (11) formed in a first well (N-type) and a second well (P-type) of a semiconductor substrate, supplied with a first supply voltage (V.sub.ss) and a second supply voltage (V.sub.cc) higher than the first supply voltage, and activated when a first well bias voltage (V.sub.BP1) is applied to the first well (N-type) and a second well bias voltage (V.sub.BN1) is applied to the second well (P-type); a second circuit (201; 202) formed in a third well (N-type) and a fourth well (P-type) of the same semiconductor substrate as above, supplied with the first supply voltage (V.sub.ss) and a third supply voltage (V.sub.cc2) higher than the first supply voltage but different from the second supply voltage (V.sub.cc), and activated when a third well bias voltage (V.sub.BP2) is applied to the third well (N-type) and a fourth well bias voltage (V.sub.BN2) is applied to the fourth well (P-type); a first bias circuit (20) supplied with the first and second supply voltages (V.sub.ss and V.sub.cc), for generating and outputting the first well bias voltage (V.sub.BP1); a second bias circuit (21) supplied with the first and second supply voltages (V.sub.ss and V.sub.cc), for generating and outputting the second well bias voltage (V.sub.BN1); a third bias circuit (16) supplied with the first and third supply voltages (V.sub.ss and V.sub.cc2) for generating and outputting the third well bias voltage (V.sub.BP2); and a fourth bias circuit (17) supplied with the first and third supply voltages (V.sub.ss and V.sub.cc2) for generating and outputting the fourth well bias voltage (V.sub.BN2). In the semiconductor device, even if any of the second supply voltage (V.sub.cc) and the third supply voltage (V.sub.cc2) is first supplied, it is possible to prevent the latch-up phenomenon caused by the floated substrate potential.

Semiconductor device and SRAM having plural power supply voltages

A semiconductor memory device having memory cells arranged in a matrix, each of the memory cells having input/output terminals, word lines for selecting the memory cells, pairs of bit lines connected to the input/output terminals, bit line pulling-up means for pulling up the potential of the bit lines, bit line loading means connected to another pair of bit lines and bit line equalizing means provided for the bit lines for equalizing the potential of the bit lines by allowing conduction between the bit lines before data is read from a selected memory cell.

Semiconductor memory device having bit line equalizing means

A delay circuit is interposed between first and second circuit systems both driven by a first supply voltage. The delay circuit delays a signal applied by the first circuit system, and then transmits the delayed signal to the second circuit system. In particular, a constant voltage supply circuit generates a second supply voltage (constant voltage) on the basis of the first supply voltage, and supplies the constant voltage to this delay circuit, so that a stable constant delay time can be obtained by the delay circuit without being subjected to the influence of fluctuations of the first supply voltage. All the circuit elements are formed on the same semiconductor substrate. Further, it is preferable to construct the constant voltage supply circuit in such a way that the output voltage thereof is programmable.

Semiconductor integrated circuit for a stable constant delay time

This invention is a BiMOS logical circuit that provides a suitable output level with a limited number of components. The intermediate node of a PMOS transistor and an NMOS transistor is connected to the base of a bipolar transistor to control output voltage. The NMOS transistor is connected between the output terminal and the power source, and an output voltage approximately equal to the power supply voltage is obtained at the output terminal.

BiMOS logical circuit

The invention is a BiMOS logical circuit having a reduced number of components and increased operating speed. First and second MOS transistors are provided for, respectively, driving first and second bipolar transistors. The gates of these MOS transistors are, respectively, connected to the bases of the second and first bipolar transistors. The input terminal is connected to the gates of the MOS transistors.

Growing community of inventors

Yokohama, Japan

Yasumitsu Nozawa