Interface state behaviour of plasma grown oxides following low temperature annealing

Abstract

The effects of low temperature (≤ 600°C) annealing on the interface state density of plasma grown silicon dioxide are investigated. It has been found that the interface state density at midgap, D itm, of plasma grown oxides can be an order of magnitude higher than that of thermally grown oxides after post-oxidation annealing (POA) treatment with SiO 2/Si structure in forming gas. The differences in D itm between the plasma grown oxide and the thermally grown oxide can be reduced by performing a post-metallization annealing (PMA) process. Thus, it would appear that there exist certain states at the plasma grown Si/SiO 2 interface, which can be annealed out by atomic hydrogen, but not by molecular hydrogen, and these states are absent at the thermally grown oxide interface. The annealing rates of the PMA process decrease with the ambient pressure. A PMA treatment of the oxide in a RF hydrogen plasma can improve annealing efficiency.