Electrical and Structural Properties of High-K HfO2 on Si1-X Gex Substrates

Abstract

The changes in the electrical and physical properties of HfO2 films grown using atomic layer deposition (ALD) on Si1-XGeX (x=0.1, 0.2, 0.3) substrates after post-annealing have been studied. The migration of Ge plays a key role in reducing the capacitance equivalent thickness (CET) whilst keeping the leakage current density constant after post-annealing. The Ge atoms which have already diffused into the HfO2 upper layer during deposition are drawn back to interfacial layer. Although the thickness of interfacial layer increases, the thickness shrinkage of HfO2 upper layer and increased permittivity of both layers achieves a reduction of the capacitance equivalent thickness.