A comprehensive approach to process control

Embedded SiGe is widely used to boost the performance of the pFET device at recent technology nodes. We show that the thickness of the deposited SiGe layer has a strong impact on critical device parameters, which implies we require all process steps involved in its formation to be very strictly controlled. To achieve this we employ several methods that go beyond the usual controls on reproducibility and uniformity of etch and deposition processes. We also discuss some recommendations for incorporating these methods as part of the operational procedures in a Fab.