Surface preparation of a compound semiconductor surface, such as indium antimonide (InSb), with a triflating agent, such as triflic anhydride or a trifluoroacetylating agent, such as trifluoroacetic anhydride is described. In one embodiment, the triflating or trifluoroacetylating passivates the compound semiconductor surface by terminating the surface with triflate trifluoroacetate groups. In a further embodiment, a triflating agent or trifluoroacetylating agent is employed to first convert a thin native oxide present on a compound semiconductor surface to a soluble species. In another embodiment, the passivated compound semiconductor surface is activated in an ALD chamber by reacting the triflate or trifluoroacetate protecting groups with a protic source, such as water (H2O). Metalorganic precursors are then introduced in the ALD chamber to form a good quality interfacial layer, such as aluminum oxide (Al2O3), on the compound semiconductor surface.