Novel composite film of Ag-Si to develop an infrared (8–14 um) detector

Abstract

A composite film of Ag-Si was sputtered on the substrate of Si (111) to study the electrical properties using the Hall Effect. The composite is designed to be used to make a detector in the wavelength range of 8-14 microns. A volume fraction of 20% and 80% Ag and Si were used respectively. The sample of thickness of 2.0 microns was subjected to chemical cleaning until complete removal of the segregated layer, a thin conductive layer caused by the rising of Ag atoms to the surface. The following step after etching was the evaporation of 200Å chromium (Cr) and 2000Å gold (Au) in the chamber of the vacuum. To create lower resistance between the evaporated metals and composite, the sample was annealed at 7000°C in a RTA for 30 seconds. An I-V measurement was taken to ensure that the contacts were ohmic, i.e. linear. The final step before measuring the Hall Effect was to sand blast a cloverleaf pattern on the composite with the contact on the periphery of each leaf. Finally, Hall measurement showed average carrier concentration of 2.94E20 (cm3) and the average mobility of 86.4 (cm2/ volt-sec).