Plasma passivation of III-V semiconductor surfaces

Poor electronic properties of III-V semiconductor surfaces and semiconductor-insulator interfaces resulting from a high density of surface/interface states limit III-V device technology. For this reason, passivation of III-V surfaces, in particular plasma passivation, has received attention in the last two decades. In this chapter, we review these research efforts with emphasis on in situ and real-time diagnostic methods to detect chemical and electronic changes on surfaces upon passivation. Hydrogen-atom based plasma passivation techniques, using H₂, NH₃, and H₂S, have emerged as viable methods for removing surface states and native oxides. Improvements in III-V device performance can be made with judicious choice of the plasma operating parameters such as plasma excitation method, pressure, power, flow rate and substrate temperature. In situ and real-time surface diagnostic methods, such as photoluminescence monitoring and attenuated-total-reflection Fourier transform infrared spectroscopy (ATR-FTIR), are crucial for optimizing the process conditions.