LIGHT-INDUCED DEFECT DENSITIES IN HYDROGENATED AND DEUTERATED AMORPHOUS-SILICON DEPOSITED AT DIFFERENT SUBSTRATE TEMPERATURES

The saturated metastable defect density under AM1 (100 mW cm-2) illumi nation as well as their formation and annealing kinetics have been stu died in a large number of hydrogenated, and deuterated amorphous silic on films, prepared by plasma enhanced chemical-vapor deposition of sil ane at substrate temperatures of 250-degrees-C-450-degrees-C at differ ent deposition rates, having low stable defect densities. The hydrogen ated films exhibit a characteristic saturated defect density of (2-5) X 10(16) cm-3 independent of deposition conditions. There is no variat ion in the formation or annealing kinetics for samples with initial de fect densities < 3 X 10(15) cm-3, but samples with higher initial defe ct densities have an order-of-magnitude longer time constants. On the other hand, there is a marked reduction of the saturated defect densit y in the deuterated films when the deposition temperature is increased even though the kinetics are similar to their hydrogenated counterpar ts. This shows that the saturated metastable defect density can be var ied but is not a simple consequence of the average sample properties o r the defect kinetics.