Development of surface barrier detectors of low leakage current employing argon cold plasma assisted silicon surface cleaning prior to detector fabrication

Abstract

The performance of silicon surface barrier detectors was improved by atmospheric pressure argon cold plasma assisted surface cleaning compared to routine cleaning using organic solvents, prior to edge protection using epoxy, then followed by metallization. The silicon wafers' surfaces were exposed to plasma etching, after lapping and chemical etching. The plasma cleaning conditions were optimized with respect to feed gas composition, flow rates and exposure time. Various Au/n-Si surface barrier detectors fabricated thereof were characterized by measuring forward and reverse Current-voltage (I-V) characteristics and alpha energy spectra obtained on exposure to α-particles. The variation of alpha energy resolution with applied reverse bias voltage for each detector was also studied. The results reveal that the leakage current of the new detectors treated with cold plasma formed by a mixture of Argon and Air (90% Argon and 10% Air) was substantially lower than that of surface barrier detectors fabricated following conventional methods.