Atomic Layer Deposition of SnTe Thin Film Using Sn(N(CH₃)₂)₄and Te(Si(CH₃)₃)₂with Ammonia Coinjection

This study introduces the synthesis of conformal crystalline SnTe films through atomic layer deposition (ALD) using the sequential injection of Sn(N(CH3)2)4 and Te(Si(CH3)3)2 with NH3 coinjection. The one to one stoichiometry of the deposited SnTe films indicates the conversion of Sn(IV) to Sn(II) and the removal of Te(0) during the deposition process as a result of the redox reaction between Sn(IV) and Te2-. NH3 coinjection with Te(Si(CH3)3)2 facilitated the uniform growth of SnTe films even at high temperatures (>130 °C), where the growth was severely retarded in the absence of NH3 due to the desorption of the precursors from the substrates. The self-limiting growth rates of 93 and 150 ng·cm-2·cycle-1 (1.5 and 2.4 Å·cycle-1) were obtained at 90 and 130 °C, respectively. The process produced high-purity, crystalline-as-deposited SnTe films with a face-centered cubic structure.