Interface passivation of liquid-phase crystallized silicon on glass studied with high-frequency capacitance-voltage measurements

The passivation quality at the interface between dielectric interlayer (IL) stacks and liquid-phase crystallized silicon (LPC-Si) was investigated by means of high-frequency capacitance-voltage (C-V) measurements. The developed device structure was based on a molybdenum layer sandwiched between the glass substrate and the IL/LPC-Si stack. C-V curves were discussed in terms of hysteresis formation and capacitance relaxation. We varied the nitrogen and hydrogen content in the a-SiOxNy: H layer adjacent to the LPC-Si and studied the effects on the defect state density at the IL/LPC-Si interface (D-it) aswell as on the effective charge density in the IL (Q(IL, eff)). Both parameters are crucial for the analysis of chemical andfield-effect passivation. Furthermore, the effect of an additional hydrogen plasma treatment (HPT) on D-it and Q(IL, eff) was investigated. A Gaussian-like defect distribution at around 0.1 eV above the mid gap energy is significantly reduced by the additional HPT. With additional HPT, the lowest Dit and highest Q(IL, eff) at mid gap, i. e., D-it = (3.5 +/- 0.7) x 10(11)eV(-1) cm(-2) and Q(IL, eff) = (1.6 +/- 0.3) x 10(12) cm(-2), correspond to the passivation by an a-SiOxNy: H layerwith a lownitrogen and high hydrogen content. (C) 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim