Semiconductor device and method of fabricating the same

Abstract

A semiconductor device and a method of fabricating the same are disclosed. A reference direction for a substrate is parallel to a first or second crystallographic direction, and a patterned hard mask layer is distributed along the first crystallographic direction. For substrates with notches oriented in different crystallographic directions, the patterned mask layer may be used as a mask for forming trenches in the substrate surface. When viewed normal to a cross-section perpendicular to the substrate, each trench has a cross-sectional width decreasing from the substrate surface toward the inside of the substrate. This allows the semiconductor device to have increased light absorption and conversion efficiency. Forming the trenches by wet etching can avoid increased dark current due to damage to the trenches' side surfaces that may be caused by the use of a dry etching process. Thus, an effective improvement in terms of dark current can be achieved.