Electrical characteristics of highly reliable ultrathin hafnium oxide gate dielectric

摘要

Electrical and reliability properties of ultrathin HfO/sub 2/ have been investigated. Pt electroded MOS capacitors with HfO/sub 2/ gate dielectric (physical thickness /spl sim/45-135 /spl Aring/ and equivalent oxide thickness /spl sim/13.5-25 /spl Aring/) were fabricated. HfO/sub 2/ was deposited using reactive sputtering of a Hf target with O/sub 2/ modulation technique. The leakage current of the 45 /spl Aring/ HfO/sub 2/ sample was about 1/spl times/10/sup -4/ A/cm/sup 2/ at +1.0 V with a breakdown field /spl sim/8.5 MV/cm. Hysteresis was >100 mV after 500/spl deg/C annealing in N/sub 2/ ambient and there was no significant frequency dispersion of capacitance (>1%/dec.). It was also found that HfO/sub 2/ exhibits negligible charge trapping and excellent TDDB characteristics with more than ten years lifetime even at V/sub DD/=2.0 V.