Thermochemical behavior of hydrogen in hafnium silicate films on Si

HfSiO films on Si were sequentially annealed in vacuum, oxygen, hydrogen, or deuterium atmospheres followed by quantification of H and D by nuclear reaction analysis. The observed H(D) incorporation and desorption behaviors are discussed in terms of two H bonding states in the films. Si-H bonds are easier to break thermally and formation of these bonds can be suppressed by annealing in O-2 to fully oxidize Si atoms. O-H bonds are harder to break thermally. However, hydrogen atmospheres ease desorption of H in O-H species. The results indicate possible paths to achieve low H content in HfSiO gate dielectrics. (c) 2006 American Institute of Physics.