Controlling the fixed charge and passivation properties of Si(100)Al2O3 interfaces using ultrathin SiO2 interlayers synthesized by atomic layer deposition

Al2O3 synthesized by atomic layer deposition (ALD) on H-terminated Si(100) exhibits a very thin (~1¿nm) interfacial SiOx layer. At this interface, a high fixed negative charge density, Qf, is present after annealing which contributes to ultralow surface recombination velocities¿~5¿nm), the polarity of the effective charge density changed from negative to positive. The observed changes in Qf and the associated field-effect passivation had a significant influence on the injection-level-dependent minority carrier lifetime of Si.