Interface stability during the growth of Al2O3 films on Si(001)

We grew thin Al2O3 films on Si(001)-2x1 surfaces using three different growth procedures and investigated the Al2O3 /Si(001) interface structure and stability for each case. We observed that stacked Al2O3 film grew with an atomically abrupt interface on Si(001). However, depositing a relatively thick initial Al film on Si(001) followed by oxidation, resulted in Al2O3 films being formed having a significantly roughened interface with the Si(001). The interfacial roughness was attributed to the Si-Al interdiffusion near the interfacial region, which with increasing oxidation time, resulted in a nonuniform interfacial region being formed with Al-O-Si compounds. In the growth of Al2O3 film on an Al2O3 prelayer/Si(001) system by depositing Al in an oxygen ambient, about one layer of roughening of the Si substrate occurred at the interface, which was attributed to nonuniform oxidation of the Si substrate. Furthermore, the Al2O3 film growth rate was very slow in this case. These results indicate that the growth procedure adopted to form Al2O3 films plays an important role in controlling the composition and structure of the Al2O3/Si(001) interface. (C) 2003 American Institute of Physics.