US Patent 7902540 - Fast p-i-n nanowire photodetector

http://www.freepatentsonline.com/7902540.html

This patent from IBM teaches nanowire photodetectors as a replacement for lateral trench detectors which can simplify manufacturing. Claim 1 reads:

1. A p-i-n photodetector comprising:

an array of semiconductor nanowires having a first conductivity type dopant present within an entirety of each of the semiconductor nanowires, the array of semiconductor nanowires disposed vertically on a surface of an underlying semiconductor substrate of said first conductivity type;

an intrinsic semiconductor material located on said surface of said semiconductor substrate and directly on a top surface and sidewall surfaces of each semiconductor nanowire of said array; and

a semiconductor material of a second conductivity type located directly on a surface of said intrinsic semiconductor material, wherein said second conductivity type is different from said first conductivity type, and said array of semiconductor nanowires having the first conductivity type and the semiconductor material of the second conductivity type provide p-type and n-type elements of the p-i-n photodetector and the intrinsic semiconductor material separates the p-type and n-type elements of the p-i-n photodetector, and wherein a portion of said semiconductor material of said second conductivity is spaced apart from the surface of the underlying semiconductor substrate by a portion of said intrinsic semiconductor material that is located on said surface of said underlying semiconductor substrate.