Technique for fabricating multilayer color sensing photodetectors

Abstract

A multilayer color-sensing photodetector is fabricated in a semiconductor wafer having a single crystal structure to form a first, second and third layer of single crystal semiconductor material. A dielectric layer is formed that completely surrounds each single crystal region. A blocking layer is applied to prevent ion implantation where not desired. Ions are implanted into a predefined implant area. The semiconductor wafer is heated to create a dielectric layer part way through the single crystal semiconductor region. The second layer of single crystal semiconductor materials is formed by depositing a single crystal or polycrystalline material and annealing it to form a single crystal semiconductor. The deposited semiconductor layer is masked and etched to obtain single crystal regions directly above the previous layer. A blocking layer is applied and an ion implant is performed. After heating, there is left a region of single crystal silicon that has its sides and bottom surrounding by a dielectric border. The third layer of semiconductor material is likewise deposited and processed to form a top layer of single crystal semiconductor material.