发明授权
US5572461A Static random access memory cell having a capacitor and a capacitor
charge maintenance circuit
失效
具有电容器和电容器电荷维持电路的静态随机存取存储单元
- 专利标题: Static random access memory cell having a capacitor and a capacitor charge maintenance circuit
- 专利标题(中): 具有电容器和电容器电荷维持电路的静态随机存取存储单元
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申请号: US388873申请日: 1995-02-14
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公开(公告)号: US5572461A公开(公告)日: 1996-11-05
- 发明人: Fernando Gonzalez
- 申请人: Fernando Gonzalez
- 申请人地址: ID Boise
- 专利权人: Micron Technology, Inc.
- 当前专利权人: Micron Technology, Inc.
- 当前专利权人地址: ID Boise
- 主分类号: G11C11/402
- IPC分类号: G11C11/402 ; H01L27/11 ; G11C11/00
摘要:
The present invention is a three-transistor (3-T) SRAM cell that is made up of a half latch in combination with a dynamic random access memory (DRAM) cell. In a DRAM cell, the "0" bit state is represented by a discharged cell capacitor--a stable state. The "1" bit state, on the other hand, is represented by a charged cell capacitor--an unstable state, since the capacitor leaks rapidly toward the discharged "0" bit state. The new 3-T SRAM cell incorporates a latch which maintains the charge on the cell capacitor when the cell is in a "1" bit state. The cell circuitry includes a cell access transistor coupled to a capacitor, a pull-down transistor, and a P-channel thin film transistor (TFT) which acts as the capacitor pull-up device, the gate of the P-channel TFT also being the drain of the pull-down transistor. A separate polycrystalline silicon layer functions as the substrate of the TFT pull-up device. The 3-T SRAM cell is one half the size of a 4-T SRAM cell and about twice the size of a DRAM cell.
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