Abstract: A method includes forming a pad layer. The pad layer includes a first portion over a first part of a semiconductor substrate, and a second portion over a second part of the semiconductor substrate. The first portion has a first thickness, and the second portion has a second thickness smaller than the first thickness. The semiconductor substrate is then annealed to form a first oxide layer over the first part of the semiconductor substrate, and a second oxide layer over the second part of the semiconductor substrate. The pad layer, the first oxide layer, and the second oxide layer are removed. A semiconductor layer is epitaxially grown over and contacting the first part and the second part of the semiconductor substrate.

Abstract: The method includes performing a well implantation process to dope a dopant into a semiconductor substrate; after performing the well implantation process, performing a flash anneal on the semiconductor substrate, the flash anneal including a first preheat step and a first annealing step after the first preheat step, the first preheat step performed at a preheat temperature ranging from about 200° C. to about 800° C., the first annealing step having a peak temperature ramp profile, the peak temperature ramp profile having a peak temperature ranging from about 1000° C. to about 1200° C.; after performing the flash anneal, performing a rapid thermal anneal (RTA) on the semiconductor substrate, the RTA including a second preheat step, the first preheat step of the flash anneal being performed for a shorter duration than the second preheat step of the RTA.