(Et3Si)2Se as a precursor for atomic layer deposition: growth analysis of thermoelectric Bi2Se3

Abstract

An atomic layer deposition (ALD) process was developed for an important thermoelectric material Bi₂Se₃ utilizing dechlorosilylation reactions between BiCl₃ and (Et₃Si)₂Se precursors. The applicability of this alkylsilyl selenide precursor was confirmed, as reactions with BiCl₃ produced good quality thin films with low impurity contents. Saturation of the growth rate with regards to the pulse lengths of both precursors indicated that the Bi₂Se₃ process had characteristic ALD properties. Also, the film thickness corresponded linearly with increasing number of deposition cycles. No ALD window was discovered and the growth rates decreased significantly with increasing temperatures, similarly to other ALD processes utilizing alkylsilyl chalcogenide precursors. Nevertheless, high growth rates of 1.6 Å per cycle occurred at 160 °C. In addition, a good thermoelectric response was shown.