36results about How to "Improve refresh feature" patented technology

A refresh characteristic of a DRAM memory cell is improved and the performance of a MISFET formed in the periphery thereof and constituting a logic circuit is improved. Each gate electrode in a memory cell area is formed of p type polycrystalline silicon, and a cap insulating film on each gate electrode and a sidewall film on the sidewall thereof are formed of a silicon oxide film. A polycrystalline silicon film formed on the gate electrodes and between the gate electrodes is polished by a CMP method, and thereby contact electrodes are formed. Also, sidewall films each composed of a laminated film of the silicon oxide film and the polycrystalline silicon film are formed on the sidewall of the gate electrodes in the logic circuit area, and these films are used as a mask to form semiconductor areas. As a result, it is possible to reduce the boron penetration and form contact electrodes in a self-alignment manner. In addition, the performance of the MISFET constituting the logic circuit can be improved.

In a data holding mode, data storage in a one bit / one cell scheme in a normal operating mode are rearranged into data storage in a twin-cell mode in which data are stored in a one bit / two cell scheme. In the twin-cell mode, two sub word lines are simultaneously driven into a selected state, and storage data of memory cells are read out on both of bit lines in a pair, to perform a sense operation. Thus, the read-out voltage can be increased to improve the data retention characteristics for lengthening a refresh interval, resulting in a reduced power consumption in the data holding mode.

A semiconductor device includes a substrate comprising a trench; a gate dielectric layer formed over a surface of the trench; a gate electrode positioned at a level lower than a top surface of the substrate, and comprising a lower buried portion embedded in a lower portion of the trench over the gate dielectric layer and an upper buried portion positioned over the lower buried portion; and a dielectric work function adjusting liner positioned between the lower buried portion and the gate dielectric layer; and a dipole formed between the dielectric work function adjusting liner and the gate dielectric layer.

A method for fabricating a transistor of a semiconductor device is provided. The method includes: forming device isolation layers in a substrate including a bottom structure, thereby defining an active region; etching the active region to a predetermined depth to form a plurality of recess structures each of which has a flat bottom portion with a critical dimension (CD) larger than that of a top portion; and sequentially forming a gate oxide layer and a metal layer on the recess structures; and patterning the gate oxide layer and the metal layer to form a plurality of gate structures.

A method for forming an isolation layer of a semiconductor device is disclosed, which comprises the steps of: etching a silicon substrate having a cell region and a peripheral circuit region, forming a first trench having a first size in the cell region, and forming a second trench having a second size, which is larger than the first size of the first trench, in the peripheral circuit region; forming a sidewall oxide layer on surfaces of the first trench and the second trench; sequentially depositing a liner nitride layer and a liner oxide layer on a resultant substrate inclusive of the sidewall oxide layer; performing a plasma pre-heating process using O2+He with respect to the resultant substrate in an HDP CVD process chamber and selectively oxidizing a portion of the liner nitride layer remaining on a bottom of the second trench in the peripheral circuit region; continuously depositing an HDP oxide layer on the resultant substrate having been subjected to the plasma pre-heating process, thereby filling the trenches; and performing a chemical mechanical polishing process with respect to the HDP oxide layer.

In a semiconductor device, an internally-generated power supply voltage VPP is monitored. If the internally-generated power supply voltage VPP is lower than a lower limit voltage, serial refresh is selected as a double refresh operation mode. In the serial refresh, double refresh for a pair address is inserted in a next refresh cycle. By the serial refresh, decrease of the internally-generated power supply voltage VPP is suppressed.

Double refresh executing means is changed in accordance with a manner (distributed refresh or burst refresh) of a refresh command so as to suppress a drop of internal power supply that occurs upon double refresh.

A recess gate-type semiconductor device includes a gate electrode having a recessed portion at least partially covering a recess trench in an active region, and source / drain regions disposed in the active region that are separated by the gate electrode. The recess trench is separated from sidewalls of a device isolation region in a first direction and contacts sidewalls of the device isolation region in a second direction. The width of the recess trench of the active region in the second direction may be greater than the width of the source / drain regions in the second direction, and the recessed portion of the gate electrode may have tabs protruding in the first direction at its corners. Therefore, the semiconductor device has excellent junction leakage current and excellent refresh characteristics.

This invention relates to a method and resulting structure, wherein a DRAM may be fabricated by using silicon midgap materials for transistor gate electrodes, thereby improving refresh characteristics of access transistors. The threshold voltage may be set with reduced substrate doping requirements. Current leakage is improved by this process as well.

A method for fabricating a semiconductor device includes: forming a gate trench in a semiconductor substrate; forming a gate dielectric layer over a bottom surface and sidewalls of the gate trench; forming a first work function layer over the gate dielectric layer; doping a work function adjustment element to form a second work function layer which overlaps with the sidewalls of the gate trench; forming a gate conductive layer that partially fills the gate trench; and forming doped regions inside the semiconductor substrate on both sides of the gate trench.

A method for forming a semiconductor device having recess channel includes forming a hard mask film pattern for exposing first regions for forming the trenches on a semiconductor substrate; forming first trenches by a first etching process using the hard mask film pattern as a mask, and removing the hard mask film pattern; forming a barrier film on the semiconductor substrate including the first trenches; forming an ion implantation mask film for exposing the first trenches on the barrier film; forming an ion implantation region in the semiconductor substrate below the first trenches using the ion implantation mask film and the barrier film; forming bulb-shaped second trenches by a second etching process using the ion implantation mask film and the barrier film as a mask, so that bulb-type trenches for recess channels, each including the first trench and the second trench, are formed; and removing the ion implantation mask film and the barrier film.

Each cell unit has a cell plate electrically isolated from the cell plates in the other cell units.

A semiconductor memory device and a self-refresh method in which the semiconductor memory device includes a plurality of input / output ports having respective independent operation, a period of self-refresh through one of the plurality of input / output ports being subordinate to a kind of operation through another input / output port. Whereby, a refresh characteristic in a multi-port semiconductor memory device including a dual-port semiconductor memory device may be improved.

In the semiconductor device, a line-type buried gate is formed by burying a non-operating gate (isolation gate) with a polysilicon material to reduce a work function and a Gate Induced Drain Leakage (GIDL) caused by the non-operating gate, resulting in improvement of refresh characteristics of the semiconductor device. Operating gates including a metal conductive material may be formed in a separate step.