| 摘要 |
In an integrated circuit comprising both PMOSFETs (200) and NMOSFETs (100), carrier mobility is enhanced on both types of FETs using dual stressed films providing different stresses to the channels of the PMOSFETs (200) and NMOSFETs (100). The adverse impact of having both layers of stressed films along the boundary between different types of films is eliminated by utilizing self-alignment of the edges of a second stressed film (70) to a preexisting edge of a first stressed film (50). At the boundary between the two stressed films (50, 70), one stressed film abuts another but no stressed film overlies another stressed film. By avoiding any overlap of stressed films (50, 70), the stress exerted on the MOSFET channels is maximized. On top the second sressed film (70) has an angled ledge that is self-aligned to the edge of the first stressed film (50).
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