On the impact of interfacial SiO_x‐layer on the passivation properties of PECVD synthesized aluminum oxide

Abstract

The interface passivation of a ‐AlOx/a ‐SiNx:H stacks deposited on p‐type silicon by plasma enhanced chemical vapor deposition is investigated by means of charge carrier lifetime and surface photovoltage measurements. To control the quality of the interface, we performed different surface preparation steps prior to a ‐AlOx/a ‐SiNx:H stack deposition. Our investigation is focussing on the interface passivation upon post‐deposition thermal treatments such as annealing at 425 °C and firing as applied in the silicon solar cell industry. We demonstrate that the interface recombination is mainly controlled by the interface state density as demonstrated by lifetime and SPV measurements. The increase of the negative charge density after thermal steps as revealed by FTIR spectroscopy evidences that the field effect has at least an enhancing effect in improving the passivation level (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Improved Si/SiOx interface passivation by ultra-thin tunneling oxide layers prepared by rapid thermal oxidation

“…This reduces the Fermi-level pinning and enables the formation of carrier selective contacts. Such tunneling oxidenanolayers can also be used in surface passivation stacks for solar cells [5,6], as barrier layers in Si-based multi-junction quantum well Due to all these different application areas, much of research was spent on the growth of silicon oxide-nanolayers and the characterization of the Si/SiO 2 interface. Research on understanding and enhancing the properties of ultra-thin RTO oxide-nanolayers was mainly driven by the MOS transistor and microelectronics technology.…”

High quality tunneling oxides for passivated contacts and heterojunctions for high efficiency silicon solar cells

“…Ultra-thin silicon oxide nanolayers have received much attention as intermediate layers in passivated contacts [1]- [3], metal insulator semiconductor solar cells [4]- [6], surface passivation stacks [7], [8], as barrier layers in Si-based multijunction quantum well solar cells [9] and for the passivation of the heterojunction interface of a-Si/c-Si heterojunction solar cells [10]. The main quality factors are the uniform thickness allowing charge carrier tunneling and the stable chemical passivation quality at the Si/SiO x interface.…”

Improving ALD-Al2O3 Surface Passivation of Si Utilizing Pre-Existing SiOx

“…Comparing the surface passivation of Al 2 O 3 deposited on SiO x formed in different conditions is likely to lead to increased understanding of how this layer affects the surface passivation. The effect of various pretreatments on the surface passivation of Al 2 O 3 has been investigated previously [25]- [30], demonstrating significant differences. However, as these studies do not compare the surface saturation current density, J 0s , considered to be the most useful metric to quantify surface passivation of dielectrics with high Q fix [31], it is challenging to establish a general method.…”

“…However, as these studies do not compare the surface saturation current density, J 0s , considered to be the most useful metric to quantify surface passivation of dielectrics with high Q fix [31], it is challenging to establish a general method. However, methods resulting in a thin SiO x or SiC x layer forming prior to Al 2 O 3 deposition appear to yield better results than when depositing directly on H-terminated Si [25], [30], [32], [33].…”