Surface passivation of high-purity silicon detectors

The reverse current characteristics of the surface-barrier diodes depend strongly upon the surface treatment and the atmosphere in which the detector was fabricated and stored. Reduction of the surface leakage current was accomplished by evaporating some oxide (WO3 or Sn2) on the surface of n-type silicon before gold electrode deposition. The reverse current of the order of 10-7A/cm2 at the bias of 300V was thus obtained. The stability of the detectors has been satisfactory at least for 24 hours when they are operated in vacuum. Surface treatment of p-type silicon detectors is also described. (author)