IDENTIFICATION OF GENERATION-RECOMBINATION CENTERS AND TRAPS IN VIRGIN AND FOWLER-NORDHEIM STRESSED METAL-OXIDE-SEMICONDUCTOR FIELD-EFFECT TRANSISTORS BY LOW-TEMPERATURE CHARGE-PUMPING TECHNIQUE

Low temperature charge pumping (CP) current measurements were carried out on 100 mu m/10 mu m N-channel metal-oxide-semiconductor (NMOS) transistors to investigate the interface state density. Interface states comprise traps and generation-recombination (g-r) centers. By measuring the CP current at different pulse frequencies at low temperatures, where the emission time constant of the traps is larger, the distribution of traps is determined distinct from that of the g-r centers. The formation of traps and g-r centers due to Fowler-Nordheim (F-N) injection at 77 K was studied by using this technique. It was shown that, immediately after the stress, F-N stress at 77 K creates more traps than g-r centers. When the temperature was raised to room temperature following stress at 77 K, the transformation from traps to g-r centers was observed. In alternating positive and negative F-N stress, positive F-N stress anneal out some of the traps generated during the previous negative F-N stress.