Surface Preparation to Obtain Good I-V Characteristics on Germanium Lithium Diodes

High voltage breakdown low current diodes have been made by the simple and reproducible process of quenching the final H202-HF etch of the diode with an acqueous salt solution. Of those salts tried CaCl2 gives the best overall performance. Planar diodes 28 mm diameter and 5 mm drift depth have been made with leakage currents < 5×10-10 A for fields up to 600 V/mm. The diode surface noise on these units was less than 0.3 keV. The surface treatment also gives some surface passivation.