Gad, K.; Vössing, D.; Balamou, P.; Hiller, D.; Stegemann, B.; Angermann, H.; Kasemann, M.: Improved Si/SiOχ interface passivation by ultra-thin tunneling oxide layers prepared by rapid thermal oxidation. Applied Surface Science 353 (2015), p. 1269-1276
10.1016/j.apsusc.2015.07.060
Abstract:
ABSTRACT: We analyze the influence of different oxidation methods on the chemical passivation quality of silicon oxide-nanolayers on crystalline silicon wafers with surface photo voltage and quasi-steady-state photo conductance measurements. We present a simple method by means of rapid thermal oxidation (RTO) and subsequent annealing in forming gas, which requires no complex surface pre-treatment or surface pre-conditioning after cleaning. This technique allows a reproducible preparation of high-quality ultra-thin oxide-nanolayers (1.3–1.6 nm) with a nearly intrinsic energetic distribution of interface states and a defect density of states of only 1 × 1012 cm−2 eV−1 at the minimum of the distribution. These results are compared with silicon oxide-nanolayers prepared by wet chemical oxidation and plasma oxidation where only a slight reduction of the interface defect density is achieved by subsequent anneal in forming gas environment. Furthermore, it is shown that applying the RTO oxide-nanolayer as an intermediate layer between Si and an a-SiNx:H layer, leads to a significant improvement of the surface passivation quality.