(Invited) Aluminium Oxide Atomic Layer Deposition on Semiconductor Substrates

Abstract

Al2O3 Atomic Layer Deposition (ALD) on semiconductor substrates finds potential applications in CMOS devices, memory devices, solar cells, etc. In this paper, we study the TMA/H2O ALD of Al2O3 on Si, Ge and GaAs substrates. Total reflection X-Ray Fluorescence (TXRF) is used to investigate the growth-per-cycle evolution during the early ALD reaction cycles. TXRF demonstrates growth inhibition from the second reaction cycle on many substrates, including conventionally used fully hydroxylated SiO2. Theoretical calculations, based on Density Functional Theory, indicate the formation of electron deficient bonds at the Al2O3/semiconductor interface, by interaction between neighboring monomethyl aluminium surface species. Both experiment and theory thus indicate that the surface chemistry of Al2O3 ALD of is more complex than previously described.