| 摘要 |
A method for forming four transistors static-random-access-memory. The method comprises: provide a substrate which at least comprises a cell region and a periphery region, wherein the cell region comprises a first P-type region, a second P-type region, a first N-type region and a second N-type region, the periphery region comprising numerous periphery P-type regions and numerous periphery N-type regions. cover the first P-type region, the second P-type region and the periphery P-type regions by a first photoresist. form numerous N-type sources and numerous N-type drains in the first P-type region, the second P-type region and the periphery P-type regions. remove the first photoresist. Use a second photoresist to cover the periphery N-type regions and some the N-type drains which are located in both the first N-type region and the second N-type region. Performing a large angle implanting process to form numerous P-type enlarged drains and numerous P-type enlarged sources in the periphery P-type regions, the first P-type region and the P-type second region, wherein numerous P-type extra sources also are formed on outsides of some the N-type drains which are located in both the first N-type region and the second N-type region.
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