Metal-oxide-semiconductor instability produced by electron-beam evaporation of Aluminum gates

The production of defect states in the oxide of MOS capacitors during the electron-beam metallization process was identified as the cause of the threshold voltage instability experienced at elevated temperatures with negative bias on the gate. Both n- and p-type silicon substrates, (100) and (111) oriented, with resistivities ranges from 0.5- 10 Ω . cm were used. The oxides were thermally grown in dry oxygen ambient with 0.3-percent HCI. During the thermal negative bias condition, trapped holes in the oxide were found close to the Si-Si0
₂
interface.