High-stress films were used to introduce dislocations lithographically to various densities and in various locations during the fabrication of ion-implanted n-on-p diodes. After fabrication, the diodes were characterized by means of variable temperature I-V and noise measurements. The diodes were then stripped and etched in order to quantify the density and distribution of the dislocations. The effects of these process-induced dislocations were analyzed and compared to the effects of as-grown dislocations and sub-grain boundaries. In general, high densities of as-grown or process-induced dislocations in n-on-p ion-implanted diodes severely degraded device performance by producing field-dependent dark current. At 77K, dislocation densities which were greater than about 5 x 106/cm2 could produce dark current densities which exceeded the diode diffusion current. Dislocations which were located near to the outer periphery of the diode produced some 10 times the dark current which was due to interior dislocations. Grain boundaries, sub-grain boundaries, and twins also produced sufficient field-dependent dark current to limit diode performance at 77K. The dark current which was produced by dislocations was almost independent of temperature. This suggested that there should be rather severe limitations on dislocation densities for low-temperature diode operation.

R.S.List: Journal of Electronic Materials, 1993, 22[8], 1017-25