Study of zinc doped In_0.53Ga_0.47As/InP/InAlAs/InP heterostructures by time-of-flight; magnetic secondary ion spectrometry and high-energy x-ray photoelectron spectroscopy

In this article, we demonstrate that the combination of ToF-SIMS, magnetic SIMS (M-SIMS), and high-energy x-ray photoelectron spectroscopy (HAXPES) is a powerful, comprehensive approach to study the quality of buried interfaces in III–V-based heterostructures. This multitechnique method enables us to track rigorously possible interdiffusion of key elements (In, Ga, As, Al, P) and dopants. Sharp interfaces were observed from ToF-SIMS profiles acquired with an upward depth resolution as low as 1.5 nm using a Cs⁺ sputtering source. For the detection of Zn doping in the layers, M-SIMS was preferred to ToF-SIMS thanks to its superior sensitivity. HAXPES was finally found to be a very complementary technique to check the abruptness of the top InGaAs/InP buried interface, taking benefit of its deeper probing ability when compared to the usual lab XPS. Our results confirm the high quality of the heterostructure with abrupt interfaces, no interdiffusion, and good control of the doping with an effective InAlAs spacer blocking Zn diffusion in InP.