Application of Al2O3 film for stabilization of charge properties of the SiO2/p-Si interface

The influence of aluminum oxide films obtained by high-frequency cathode sputtering of an Al2O3 target in argon atmosphere on charging properties of the SiO2/p-Si interface was investigated. High-frequency C-V characteristics for MIS-structure with one-layer dielectric films: SiO2 (0,10 µm and 0,36 µm), Al2O3 (0,14 µm) – and its double-layers compositions were measured. Experiment was carried out with a KDB-4.5 and a KDB-5000 substrates. Some electrophysical parameters of the obtained films such as UFB and Qss were calculated. Based on experimental results it was confirmed that the embedded negative charge of Al2O3 film prevented the formation of the inversive layer on p-Si surface by compensation of the embedded positive charge of SiO2 film and enhancement of semiconductor surface with majority charge carriers and, thus, allowed stabilization of charge properties of the SiO2/p-Si interface. The applicability of Al2O3 film as additional dielectric covering for manufacture technology of photodiodes on high-resistance p-Si was confirmed by applying on a multi-element p-i-n photosensitive element (PE) as an example. It was established that passivation of silicon dioxide on periphery and between the elements of PE by Al2O3 film improved I-V characteristics and insulation resistance, which lead to increased yield rate of photodiodes.