Abstract:
In a semiconductor storage device such as a phase change memory, a technique which can realize high integration is provided. The semiconductor storage device includes a phase change thin film 101 having two stable phases of a crystal state with low electric resistance and an amorphous state with high electric resistance, upper plug electrodes 102 and 103 provided on one side of the phase change thin film 101, a lower electrode 104 provided on the other side of the phase change thin film 101, a selecting transistor 114 whose drain/source terminals are connected to the upper plug electrode 102 and the lower electrode 104, and a selecting transistor 115 whose drain/source terminals are connected to the upper plug electrode 103 and the lower electrode 104, and a first memory cell is configured with the selecting transistor 114 and a phase change region 111 in the phase change thin film 101 sandwiched between the upper plug electrode 102 and the lower electrode 104, and a second memory cell is configured with the selecting transistor 115 and a phase change region 112 in the phase change thin film 101 sandwiched between the upper plug electrode 103 and the lower electrode 104.
Abstract:
A semiconductor device comprises a plurality of memory cells, a central processing unit, a timer circuit which times a RESET time, and a timer circuit which times a SET time. A threshold voltage of an NMOS transistor of each memory cell is lower than that of the peripheral circuit, thereby easily executing a RESET operation. The direction of a flowing current is changed across the RESET operation and the SET operation, and the bit lines are activated at high speed, thus preventing system malfunctions. Further, the semiconductor device can overcome such problems as a wrong write operation and data destruction, resulting from the variation in the CMOS transistors when operating phase change elements with minimum size CMOS transistors at a core voltage (e.g. 1.2 V). According to the present invention, stable operations can be realized at a low voltage, using minimum-size cell transistors.
Abstract:
In non-volatile storage device using a variable resistance material, when a crystal state and a noncrystalline state co-exists in the variable resistance material, a crystallization time is shorted, resulting in decrease of the time to maintain information stored. Heat radiation is not rapidly performed during rewriting and thus it takes a long time to complete the rewriting due to a low thermal conductivity of a material contacting the variable resistance material. According to the present invention, a contact area between a variable resistance material and a lower electrode, and a contact area between the variable resistance material and an upper electrode are made equal to each other, thereby unifying a current path. The invention provides a structure in which a material having a high thermal conductivity is disposed so as to contact a sidewall of the variable resistance material, and its end portion is made to contact the lower electrode as well.
Abstract:
A semiconductor non-volatile storage device of the present invention which lets a memory cell directly drive up to a local bit line, wherein the output of the local bit line is received by a gate electrode of a separately-provided signal amplifying transistor, and the signal amplifying transistor is used to drive a global bit line having a large load capacity. Since an amplifying transistor having a drive power higher than a memory cell drives the parasitic capacity of a global bit line, information stored in a memory cell can be read out at high speed. Therefore, the storage device is used for storing program codes for controlling microcomputers or the like to thereby enhance a system performance.
Abstract:
A semiconductor device includes a plurality of nonvolatile memory cells (1). Each of the nonvolatile memory cells comprises a MOS type first transistor section (3) used for information storage, and a MOS type second transistor section (4) which selects the first transistor section. The second transistor section has a bit line electrode (16) connected to a bit line, and a control gate electrode (18) connected to a control gate control line. The first transistor section has a source line electrode (10) connected to a source line, a memory gate electrode (14) connected to a memory gate control line, and a charge storage region (11) disposed directly below the memory gate electrode. A gate withstand voltage of the second transistor section is lower than that of the first transistor section. Assuming that the thickness of a gate insulating film of the second transistor section is defined as tc and the thickness of a gate insulating film of the first transistor section is defined as tm, they have a relationship of tc
Abstract:
A semiconductor device, which ensures device reliability especially in fine regions and enables great capacitance and high-speed operations, has memory cells including, in a first region of a main surface of a semiconductor substrate, a gate insulating film, a floating gate electrode, an interlayer insulating film, a control gate electrode, and source and drain regions of the second conduction type arranged in a matrix, with a shallow isolation structure for isolating the memory cells. When using a shallow structure buried with an insulating film for element isolation, the isolation withstand voltage in fine regions can be prevented from lowering and the variation in threshold level of selective transistors can be reduced. When the memory cells in a memory mat are divided by means of selective transistors, the disturb resistance of the memory cells can be improved.
Abstract:
A semiconductor device includes a plurality of nonvolatile memory cells (1). Each of the nonvolatile memory cells comprises a MOS type first transistor section (3) used for information storage, and a MOS type second transistor section (4) which selects the first transistor section. The second transistor section has a bit line electrode (16) connected to a bit line, and a control gate electrode (18) connected to a control gate control line. The first transistor section has a source line electrode (10) connected to a source line, a memory gate electrode (14) connected to a memory gate control line, and a charge storage region (11) disposed directly below the memory gate electrode. A gate withstand voltage of the second transistor section is lower than that of the first transistor section. Assuming that the thickness of a gate insulating film of the second transistor section is defined as tc and the thickness of a gate insulating film of the first transistor section is defined as tm, they have a relationship of tc
Abstract:
A semiconductor device, which ensures device reliability especially in fine regions and enables great capacitance and high-speed operations, has memory cells including, in a first region of a main surface of a semiconductor substrate, a gate insulating film, a floating gate electrode, an interlayer insulating film, a control gate electrode, and source and drain regions of the second conduction type arranged in a matrix, with a shallow isolation structure for isolating the memory cells. When using a shallow structure buried with an insulating film for element isolation, the isolation withstand voltage in fine regions can be prevented from lowering and the variation in threshold level of selective transistors can be reduced. When the memory cells in a memory mat are divided by means of selective transistors, the disturb resistance of the memory cells can be improved.
Abstract:
A parallel connection-type nonvolatile memory semiconductor device comprises a plurality of memory cells disposed on a semiconductor substrate in matrix form, each including a gate insulating film, a floating gate electrode, an interlayer film and a control gate electrode successively formed so as to cover a channel region on a main surface of the semiconductor substrate, of a first conductivity type; a second conductivity type source and drain regions formed on the semiconductor substrate on both sides opposite to each other, of the floating gate electrode so as to interpose a channel region located under the floating gate electrode therebetween; a first semiconductor region which is adjacent to the drain region and formed by introducing a second conductivity type impurity in the direction of the channel region placed under the floating gate electrode from an end on the drain side, of the floating gate electrode, and which is substantially lower than the drain region in impurity concentration; and a punch-through stopper layer which is adjacent to the first semiconductor region and formed by introducing a first conductivity type impurity in the direction of the channel region placed under the floating gate electrode from an end on the drain side, of the floating gate electrode, and which is substantially higher than the channel region in impurity concentration, and wherein the source regions and drain regions of the plurality of nonvolatile memory cells are parallel-connected to one another in respective columns, word lines some of which constitute the control gate electrodes of the plurality of nonvolatile memory cells, extend in respective rows, a voltage is applied to at least one word line, which is set so as to serve as a selected word line, and when carriers are stored in a floating gate electrode of each selected memory cell, a negative voltage is applied to other non-selected word lines other than the selected word line.
Abstract:
A method for settling threshold voltages of word lines on a predetermined level in an erasing processing of a non-volatile semiconductor memory device so as to speed up the erasing processing. A word latch circuit is provided for each word line and the threshold voltage of each memory cell is managed for-each word line in a selected memory block. Each word latch circuit is shared by a plurality of word lines so as to reduce the required chip area. A rewriting voltage is set for each finished non-volatile memory and the voltage information is stored in the boot area of the non-volatile memory, so that the voltage is recognized by the system each time the system is powered.