Ultrathin HfO2 gate dielectric grown by plasma-enhanced chemical vapor deposition using Hf[OC(CH3)3]4 as a precursor in the absence of O2

Hafnium oxide thin films for use in a gate dielectric were deposited at 300degreesC on p-type Si(100) substrates using a Hf[OC(CH3)(3)](4) precursor in the absence of oxygen by plasma-enhanced chemical vapor deposition. A comparison of films deposited in the absence and presence of oxygen indicated that oxygen was an important determinant in the electrical properties of HfO2 films, which were subsequently annealed in N-2 and O-2 ambients. The capacitance equivalent oxide thickness of the as-deposited Pt/HfO2/Si capacitor was approximately 17 Angstrom and abruptly increased at an annealing temperature of 800degreesC in both N-2 and O-2 ambients. The hysteresis of the as-deposited gate dielectric was quite small, about 40 mV, and that of the gate dielectric annealed at 800degreesC in an O-2 ambient was reduced to a negligible level, about 20 mV. The interface trap density of the Pt/HfO2/Si capacitors was approximately 10(12) eV(-1) cm(-2) near the silicon midgap. The leakage current densities of the as-deposited Pt/HfO2/Si capacitor and those annealed at 800degreesC in N-2 and O-2 were approximately 8x10(-4), 8x10(-5), and 3x10(-7) A/cm(2) at -1 V, respectively.