Abstract
Layers of p-type germanium can be produced by bombardment of n-type specimens using acceptor ions. Several workers have reported on Rutherford scattering experiments as a method of investigating the interstitial/substitutional ratio of implanted ions. An investigation for a single-crystal n-type germanium bombarded with B+, Ga+ and In+ ions in a non-channelled direction by means of the determination of the electrical profile is described. For ion-implanted layers sheet resistivity measurements are not suitable for determining the number of active carriers obtained for the implant because neither the depth distribution of carriers nor the influence of lattice disorder on mobility is known. Accordingly, the investigation utilises the Van-der-Pauw method for the measurement of resistivity together with Hall effect measurements combined with an anodic-oxidation layer-removal technique to establish the variation with mobility and carrier concentration/cm3 with depth and hence enables the determination of total active carriers/cm2. As part of the investigation the influence of various parameters, such as implantation energy, total dose and subsequent annealing are described together with investigations into the problems of satisfactory ohmic contacts to p-type germanium and junction isolation at the temperature of liquid nitrogen. An appendix also describes some work on Silicon.