Electric bidirectional stress effects on metal-oxide-silicon capacitors

Bidirectional electron injections were performed in thick and thin oxides o f metal-oxide-silicon capacitors under a constant oxide electric field. Res ults show that dissymmetry, due to electron trapping near both oxide interf aces, is accentuated when the oxide is thin. However electron trapping is m ore marked when oxide is thick. Two kinds of thick oxide were used: wet and dry technologies. Wet oxide contains relatively more defects than dry. Thi s is due to hydrogen incorporation in wet oxide during the oxidation proces s. But this difference is not well marked, because boron atoms injected aft er the oxidation process would deactivate hydrogen atoms. We describe the e lectron trapping by a well-known power law. The exponent of this law depend s on oxide field polarity and also on oxide thickness but is technology ind ependent. Results also show a nonexpecting behavior of tunneling current du ring bidirectional stress at a constant voltage. Here, we describe its caus es and effects. (C) 2001 American Institute of Physics.