Texas Instruments Incorporated
Superlattice photo detector

Abstract:

A photo detector includes a superlattice with an undoped first semiconductor layer including undoped intrinsic semiconductor material, a doped second semiconductor layer having a first conductivity type on the first semiconductor layer, an undoped third semiconductor layer including undoped intrinsic semiconductor material on the second semiconductor layer, and a fourth semiconductor layer having a second opposite conductivity type on the third semiconductor layer, along with a first contact having the first conductivity type in the first, second, third, and fourth semiconductor layers, and a second contact having the second conductivity type and spaced apart from the first contact in the first, second, third, and fourth semiconductor layers. An optical shield on a second shielded portion of a top surface of the fourth semiconductor layer establishes electron and hole lakes. A packaging structure includes an opening that allows light to enter an exposed first portion of the top surface of the fourth semiconductor layer.