Patent ID: 6455344
Filing Date: 2002-09-24
Classification: H01L,Y02E,Y02P

Abstract:
A method of fabricating a planar porous silicon metal-semiconductor-metal photodetector, said method comprising the following steps:(a) plating one layer of conducting material on a back side of a silicon substrate; (b) annealing the silicon substrate which is plated with conducting material on the back side in inert gas for some time; (c) applying one layer of anti-corrosion coating on the conducting material on the back side of the silicon substrate; (d) soaking the silicon substrate into an aqueous solution of HF with appropriate concentration, applying a proper amount of current, and etching the silicon surface for a proper duration to form porous silicon; (e) removing the anti-corrosion coating on the back side of the silicon substrate; (f) oxidizing the porous silicon in rapid thermal oxidation furnace for 15 to 180 seconds at 600 to 950Â° C. to increase carrier lifetime and improve the photocurrent and photosensitivity of the porous silicon photodetector; (g) placing the porous silicon substrate into a rapid thermal annealing furnace, conducting rapid thermal annealing for 15 to 180 seconds at 600 to 950Â° C. to remove defects, so that very good photocurrent response and very low dark current of the porous silicon photodetector can be obtained; and (h) plating finger type electrodes on the porous silicon to obtain a high quality planar porous silicon metal-semiconductor-metal photodetector.