| 摘要 |
The present invention provides a method for removing charged defects from a material stack including a high k gate dielectric and a metal contact such that the final gate stack, which is useful in forming a pFET device, has a threshold voltage substantially within the silicon band gap and good carrier mobility. Specifically, the present invention provides a re-oxidation procedure that will restore the high k dielectric of a pFET device to its initial, low-defect state. It was unexpectedly determined that by exposing a material stack including a high k gate dielectric and a metal to dilute oxygen at low temperatures will substantially eliminate oxygen vacancies, resorting the device threshold to its proper value. Furthermore, it was determined that if dilute oxygen is used, it is possible to avoid undue oxidation of the underlying semiconductor substrate which would have a deleterious effect on the capacitance of the final metal-containing gate stack. The present invention also provides a semiconductor structure that includes at least one gate stack that has a threshold voltage within a control range and has good carrier mobility.
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