Thermal effects on 1H and 2H distributions determined by SIMS in atomic layer deposition of HfO2 and Al2O3 using heavy water

Incorporation of deuterium using D2O as the oxidant during the atomic layer deposition of high-k gate dielectric on silicon should lead, after post metal annealing, to a better passivation of defects and interface states than this obtained with hydrogen species. However, an optimised high-k/D2O anneal is required for manufacturing high performance CMOS devices. This paper reports new investigations by SIMS on the deuterium incorporation inside thin HfO2 and Al2O3 layers deposited by atomic layer deposition using HfCl4 and trimethylaluminium (TMA), respectively and heavy water. A wide range of thermal treatments are investigated. The results highlight the hydrogen/deuterium isotope effect at different annealing temperatures. The deuterium profile shows a concentration peak at the high-k/substrate interface; however, the D dose is low and the interface peak becomes sharper at high temperature. This preferential incorporation of deuterium at high temperature could improve the interface quality and enhance the high-k device stability and reliability