Thermal Stability Study of GaP/High‐k Dielectrics Interfaces

Abstract High‐quality interface between high‐mobility III–V compound semiconductor and high‐k dielectrics is critical for achieving high electrical performance of the devices. Elemental diffusion through the high‐k dielectrics from III–V semiconductors (e.g., InP, InAs, and InGaAs) upon the atomic layer deposition process and during the postdeposition annealing (PDA) at low temperature rises a concern with the reliability of III–V compound semiconductor devices. In this work, the thermal stability of GaP/high‐k dielectrics interface has been studied in terms of elemental diffusion upon PDA, using angle‐resolved X‐ray photoelectron spectroscopy. The Ga and P oxides are below the detection limit of X‐ray photoelectron spectroscopy for the GaP/HfO₂ stack after PDA at 400 °C, and for the GaP/Al₂O₃ stack after PDA at 500 °C. Outdiffusion of Ga and P atoms through HfO₂ film is detected by time‐of‐flight secondary ions mass spectrometry after PDA at 500 and 600 °C. Highly stable GaP/high‐k dielectrics interfaces suggest that a thin barrier layer of wide bandgap GaP between the III–V semiconductor channel materials and high‐k dielectrics would benefit the reliability of the devices.