Atomic layer deposition of Al2O3 films using AlCl3 and Al(OiPr)3 as precursors

Al2O3 films have been grown by atomic layer deposition (ALD) using reactions between AlCl3 and Al(OiPr)3. In this process the aluminium alkoxide serves as both a metal and an oxygen source. No separate oxygen source is required. With this approach an Al2O3 film has been deposited on silicon without an interfacial silicon oxide layer. The film growth rate was 0.8 Å cycle−1. The residual contents of chlorine, hydrogen and carbon in the film deposited at 300 °C were 1.8, 0.7 and <0.1 at.%, respectively. The chlorine content diminished rapidly with increasing growth temperature. The permittivities and leakage current densities were comparable to the conventional Al2O3 ALD processes for thick films, but the permittivity decreased for very thin films. Post deposition annealing is required to improve electrical properties of thin films.