发明授权
- 专利标题: ESD protection structure for P-well technology
- 专利标题(中): P-well技术的ESD保护结构
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申请号: US187746申请日: 1994-01-26
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公开(公告)号: US5477413A公开(公告)日: 1995-12-19
- 发明人: Jeffrey T. Watt
- 申请人: Jeffrey T. Watt
- 申请人地址: CA San Jose
- 专利权人: Cypress Semiconductor Corp.
- 当前专利权人: Cypress Semiconductor Corp.
- 当前专利权人地址: CA San Jose
- 主分类号: H01L27/02
- IPC分类号: H01L27/02 ; H02H9/04
摘要:
An ESD protection structure for p-well technology using nMOS FETs that prevents the lock-on condition normally occurring after one FET of a multi finger structure snaps back. The multifinger structure is contained in a main p-well and channels ESDs of a first polarity from the contact pad to a metal conduit. A resistance is provided between the main p-well and the conduit. Further, the circuit channeling ESDs of a polarity opposite to the first polarity is contained in a second p-well that is distinct from the main p-well. An ESD event causes one of the fingers to snap back. Resulting drain current through that finger generates electron hole pairs in the main p-well by impact ionization. Thus generated holes, traveling to the conduit through the resistance, raise the voltage of the main p-well, and therefore shift the i-v characteristic curves of all the FETs to a point where they no longer exhibit a knee. The absence of a knee prevents the remaining fingers from being locked off by the finger that snapped back. Consequently, all FETs are turned on and ESD protection is provided by all FETs in the main p-well.
公开/授权文献
- US4863157A Method and apparatus for exercising a paralyzed limb 公开/授权日:1989-09-05
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