公开(公告)号：JP2000187980A

公开(公告)日：2000-07-04

申请号：JP35142399

申请日：1999-12-10

Applicant: ST MICROELECTRONICS INC

Inventor： TAYLOR RONALD T

IPC: G11C11/407 ,  G11C8/08 ,  G11C11/408

Abstract: PROBLEM TO BE SOLVED: To provide a method boosting a voltage level of a word line in a DRAM in a mode in which an electric field applied to a gate oxide film of a memory cell access MOSFET is reduced. SOLUTION: When a word line level reaches VDD, a word line is stopped at a VDD level by disabling a decoder. A sense amplifier is separated, and word line voltage is made to enable following bit line voltage through capacitive coupling crossing an access MOSFET of a memory cell in which reading or writing is performed. Consequently, when bit line voltage is raised, word line voltage is increased to super-high voltage. After word line voltage reaches super-high voltage, the sense amplifier is connected, word line voltage is driven toward a VDD level and also a disabled bit line is driven toward GND. At the time of finish of a word line clock signal, the voltage is a GND potential and each bit line is restored to an intermediate voltage level.

公开(公告)号：JP2000188000A

公开(公告)日：2000-07-04

申请号：JP35617999

申请日：1999-12-15

Applicant: ST MICROELECTRONICS INC

Inventor： TAYLOR RONALD T

IPC: G11C11/401 ,  G11C29/06 ,  G11C29/50 ,  G11C29/00

Abstract: PROBLEM TO BE SOLVED: To enable a stress test at a low voltage against the oxide film of a memory cell condenser by separating a sense amplifier from a bit line, initializing all nodes that are connected to the memory cell in the test control circuit, and disabling a word line booster circuit. SOLUTION: Plural pieces of memory are provided in which a first set of alternate word lines 18a and 18c connects a memory cell 40 to half bit lines b t 110 and a second set of alternate word line 18b and 18d connects the memory cell 40 to half bit lines b c 112. With each sense amplifier of DRAM put in a separation state, and with each pre-charge voltage and half bit line grounded, each word line booster circuit is disabled or a voltage level on the word line is maintained at a low level. Since the memory cell condenser of the memory cell 40 is separated from the sense amplifier, it enables the stress test on the memory cell condenser to be carried out at a low word line voltage level independently.