抄録
In germanium p-n junctions prepared by alloying indium into n-type base, electrical characteris-tics and structures of defects involved in the periphery of indium dot are discussed. From the viewpoints of both electrical characteristics and structures these defects are conviniently divided into following two types. One type of defects is found at the outermost periphery of the junction; it consists of (i) lattice defects in the immediate neighbourhood of p-n boundary, (ii) m-n junctions and (iii) micro-unevenness of p-n boundary. Electrically these are characterized by a large back-ward saturation current as well as lowand distributed values of breakdown voltage which leads to a nearly linear voltage-current relationship and to a soft breakdown haracteristics even at low temperature. The other type of the defects is found at somewhat inner part of the periphery and consists of (i) m-n junctions and (ii) lattice defects involved in the p-n boundaries near those m-n junctions. Electrically, breakdown voltage is lowerd at those regions. By an ordinary electrolytic etching, the defective structures of the former type can be easily removed while those of the latter can be hardly removed. In the samples which are perfectly free from defects of the latter type very sharp breakdown characteristic is observed. This indicates the fact that in ordinary alloyed germanium p-n junctions, breakdown characteristic is spoiled by the inclusion of these defective structures. In this work, the above conclusion in obtained from the measurements of electrical characteristics of samples, prepared through various temperature schedules of alloying process and various stages of electrolytic etching under room and liquid nitrogen temperatures. In locating the defective structures on junction surface, copper plating method is also applied as mentioned in the preceeding paper.
