Ab initio modeling of vacancies, antisites, and Si dopants in ordered InGaAs

作者：Wang Jingyang^*; Lukose Binit; Thompson Michael O; Clancy Paulette

来源：Journal of Applied Physics, 2017, 121(4): 045106.

DOI：10.1063/1.4974949

In0.53Ga0.47As, a III-V compound semiconductor with high electron mobility, is expected to bring better performance than silicon in next-generation n-type MOSFET devices. However, one major challenge to its wide scale adoption is the difficulty of obtaining high enough dopant activation. For Si-doped InGaAs, the best current experimental result, involving 10 min of furnace annealing at temperatures above 700 degrees C, yields a free electron concentration of 1.4 x 10(19) cm(-3), a value that still falls short of requirement for practical applications. In this paper, we investigate the origin of low dopant activation in InGaAs by calculating formation energies for a wide variety of single point defects (Si substutionals, Si tetrahedral interstitials, vacancies, and antisites) in Si-doped In(0.5)Ga(0.)5As in a CuAu-I type crystal structure. We find that (1) a high electron concentration can only be achieved under In/Ga-poor growth conditions, while As-poor conditions inhibit n-type doping; and (2) in heavily n-doped samples, cation vacancies V-In/Ga-(3) contribute the most to the compensation of excess Si donors via the Si (III)-V-III mechanism (III = In/Ga), thus becoming the limiting factor to higher dopant activation. Under the most favorable growth conditions for n-doping, we find the maximum carrier concentration to be 5.2 x 10(18) cm(-3) under thermal equilibrium, within an order of magnitude of the best experimental value. Published by AIP Publishing.

• 出版日期2017-1-28