ELECTRICAL EFFECTS OF RESIDUAL DEFECTS IN SI AFTER HIGH-ENERGY IMPLANTATION OF GE+ IONS AND ANNEALING

This paper describes electrical effects of residual defects after a 12 .5 MeV Ge+ ion implantation in a dose range of 10(15) to 10(16) cm-2 i nto n-type Si and subsequent annealing at 1150-degrees-C. For analysis of the samples spreading resistance profiling and reverse current mea surements of p+/n diodes were used. The results show in a peculiar man ner a reduced charge carrier concentration in the depth range between the surface and the projected range of implanted ions. For a Ge dose o f 10(15) cm-2 the reverse current of high energy implanted diodes is s ignificantly reduced inside a depletion zone close to the p/n junction . But, for a dose greater than 10(15) cm-2 an increased reverse curren t is found. It is caused by generation centres located at both sides o f the buried damage profile created by the Ge+ ions. Therefore in this paper a method will be proposed to eliminate the undesired electrical effects of high energy implantation.