本发明之半导体晶圆包括具有第一掺质浓度的底半导体层、设于底半导体层上之中间半导体层，以及设于中间半导体层上之顶半导体层。中间半导体层具有第二掺质浓度，第二掺质浓度大于第一掺质浓度。顶半导体层具有第三掺质浓度，第三掺质浓度系小于第二掺质浓度。底半导体层之侧面为半导体晶圆的外表面，且底半导体层、中间半导体层和顶半导体层之侧壁系实质对齐。

A semiconductor wafer of the present invention includes a bottom semiconductor layer having a first doping concentration, a middle semiconductor layer over the bottom semiconductor layer, and a top semiconductor layer over the middle semiconductor layer. The middle semiconductor layer has a second doping concentration greater than the first doping concentration, and the top semiconductor layer has a third doping concentration less than the second doping concentration. A lateral surface of the bottom semiconductor layer is an external surface of the semiconductor wafer, and sidewalls of the bottom semiconductor layer, the middle semiconductor layer, and top semiconductor layer are substantially aligned.