Phosphoric acid-peroxide mixture surface preparation for the improvement of InGaAs channel characteristics

InGaAs is a potential candidate for a next-generation channel material of complementary metal-oxide-semiconductor devices based on its excellent electron mobility. In this study, the surface behaviors of the InGaAs after treatments in H₃PO₄/H₂O₂/H₂O and HNO₃/H₂O₂/H₂O mixtures were investigated and compared with that after treatment in a HCl/H₂O₂/H₂O mixture. Although the presence of Cl⁻ in an acidic solution suppressed the overall etching reaction and material loss of the InGaAs surface, Cl⁻ induced the roughening of the InGaAs surface. The smallest InGaAs/Al₂O₃ interface charge trap density was observed when the InGaAs surface was prepared in the H₃PO₄/H₂O₂/H₂O solution. It was also confirmed that the H₃PO₄/H₂O₂/H₂O-treated InGaAs surface had the highest electron mobility among the samples and the lowest interfacial defect density, such as arsenic vacancies and antisites. Finally, it was concluded that surface preparation of InGaAs with H₃PO₄/H₂O₂/H₂O effectively improved the interfacial electrical properties at the metal-oxide-InGaAs semiconductor by successfully minimizing surface roughening and the interfacial defect density compared to a well-known HCl/H₂O₂/H₂O solution process.