Growth and characterization of III-N ternary thin films by plasma assisted atomic layer epitaxy at low temperatures

摘要

We report the growth and characterization of III-nitride ternary thin films (AlxGa1-xN, InxAl1-xN and InxGa1-xN) at = 500 degrees C by plasma assisted atomic layer epitaxy (PA-ALE) over a wide stoichiometric range including the range where phase separation has been an issue for films grown by molecular beam epitaxy and metal organic chemical vapor deposition. The composition of these ternaries was intentionally varied through alterations in the cycle ratios of the III-nitride binary layers (AlN, GaN, and InN). By this digital alloy growth method, we are able to grow III-nitride ternaries by PA-ALE over nearly the entire stoichiometry range including in the spinodal decomposition region (x = 15-85%). These early efforts suggest great promise of PA-ALE at low temperatures for addressing miscibility gap challenges encountered with conventional growth methods and realizing high performance optoelectronic and electronic devices involving ternary/binary heterojunctions, which are not currently possible. (C) 2015 Elsevier B.V. All rights reserved.