Abstract:
The present invention provides a semiconductor structure having at least one CMOS device in which the Miller capacitances, i-e., overlap capacitances, are reduced and the drive current is improved. The inventive structure includes a semiconductor substrate having at least one overlaying gate conductor, each of the at least one overlaying gate conductors has vertical edges; a first gate oxide located beneath the at least one overlaying gate conductor, the first gate oxide not extending beyond the vertical edges of the at least overlaying gate conductor; and a second gate oxide located beneath at least a portion of the at one overlaying gate conductor. In accordance with the present invention, the first gate oxide and the second gate oxide are selected from high k oxide-containing materials and low k oxide-containing materials, and the first gate oxide is higher k than the second gate oxide or vice-versa.