Electrical characteristics of highly reliable ultrathin hafnium oxide gate dielectric

Electrical and reliability properties of ultrathin HfO2 have been investigated. Pt electroded MOS capacitors with HfO2 gate dielectric (physical thickness similar to 45-135 Angstrom and equivalent oxide thickness similar to 13.5-25 Angstrom) were fabricated. HfO2 was deposited using reactive sputtering of Hf target with O-2 modulation technique. Leakage current of the 45 Angstrom HfO2 sample was about 1 x 10(-4)A/cm(2) at +1.0 V with a breakdown field similar to 8.5 MV/cm. Hysteresis was <100 mV after 500 degrees C annealing in N-2 ambient and there was no significant frequency dispersion of capacitance (<1%/dec.). It was also found that HfO2 exhibits negligible charge trapping and excellent TDDB characteristics with more than ten Sears life- time even at V-DD = 2.0 V.