Current transport phenomena in SiO2 films

The current–voltage characteristics are measured for a number of metal–oxide–semiconductor capacitors fabricated under three different conditions (dry oxidation, HCl oxidation, P2O5–SiO2 system). The observed current at a particular electric field is independent of the oxidation process but depends on the annealing treatment when the aluminium electrode is biased negatively. With the reversed polarity, a spread of I–U curves is observed. This is explained with the motion of mobile charged impurities introduced into SiO2 films during post metallization annealing. An instability observed at higher electric fields with the Al electrode biased negatively is attributed to double injection.