Development of electron-selective SiO2/TiO2 stack layers with superior surface passivation capacity for n-type silicon substrates (Conference Presentation)

In this work, the electron-carrier-selectivity of ALD deposited TiO2 contact on n-type and p-type c-Si wafers is presented. The optical, compositional, and diode quality dependence of TiO2 on the ALD deposition temperature were analyzed using spectroscopic ellipsometry, AFM, XPS, GI-XRD, and CV measurements. By optimizing the ALD process parameters, an impressive effective minority carrier lifetime of up to 2.3 milliseconds corresponding to an iVoc of ~700 mV was obtained from wet chemical oxide-SiO2/TiO2 passivation stack layers. Finally, the asymmetry in C-V and J-V measurements betweenTiO2/n-type and TiO2/p-type c-Si heterojunctions was examined and the electron transport selectivity of TiO2 was revealed.