Investigation on the atomic layer deposition of the Se doped Sb–Te phase change films using an alkyl-silyl precursor

We used TDMASb, Te(t-Bu)₂, and Se(SiMe₃)₂ as precursors to investigate the behavior of atomic vapor deposition (AVD) during formation of Se doped Sb–Te phase change films. The deposition was prepared by a sequential recipe for the atomic layer deposition (ALD) reaction with consideration of the electrostatic interactions between the Se alkyl-silyl precursor and the Sb and Te precursors. The Sb–Te–Se ternary films could be deposited by AVD at temperatures of 80–300 °C with fine controllability and high surface quality. The elemental composition of the films was controlled by varying the deposition temperature. The Se doping effect on the crystallization temperature and set resistance in the crystalline state was evaluated via electrical measurements and theoretical analyses by applying the glass transition temperature model and resonance bonding model. The results indicated that the incorporation of Se into Sb–Te films may provide for improved thermal stability and power consumption efficiency in phase-change random access memory (PCRAM) devices.