High sensitivity photodetectors, imaging arrays, and high efficiency photovoltaic devices produced using ion implantation and femtosecond laser irradiation
The present invention relates generally to methods for high throughput and controllable creation of high performance semiconductor substrates for use in devices such as high sensitivity photodetectors, imaging arrays, high efficiency solar cells and the like, to semiconductor substrates prepared according to the methods, and to an apparatus for performing the methods of the invention.
1. A method of controlling a photoresponse characteristic of a semiconductor device, comprising:
providing a semiconductor material having at least one surface thereof;
subjecting the surface to short-pulsed laser irradiation to roughen the surface;
annealing the surface to heal undesired lattice damage imparted by the laser irradiation;
incorporating a dopant into a region of the semiconductor material beneath said surface by ion implantation; and
annealing the surface to activate the dopant, wherein the semiconductor device has a substantially uniform photoresponse across at least a portion of the surface of the semiconductor device, wherein the substantially uniform photoresponse varies by less than 20% in said portion of the surface of the semiconductor device.
2. The method of claim 1 , incorporating said dopant into said region comprising substantially uniformly incorporating said dopant into said region of said semiconductor beneath said surface of said semiconductor material and across said portion of the surface of said semiconductor material.
3. The method of claim 1 , incorporating said dopant comprising substantially uniformly-incorporating said dopant to a concentration greater than about 0.5×10 16 atoms/cm 3 in said region of the semiconductor material to some depth beneath the surface of the semiconductor material.