First attainment of interface trap density of 3x10¹¹ eV^-1cm^-2 on oxide/p-InGaAs by in-situ Y₂O₃ deposition

Yen-Hsun Lin^1*, Hsien-Wen Wan¹, Yu-Jie Hong¹, Lawrence Bo-Yu Young¹, Yi-Ting Cheng¹, Chien-Ting Wu², Jueinai Kwo³, Minghwei Hong¹

¹Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei, Taiwan
²Taiwan Semiconductor Research Institute, Hsinchu, Taiwan
³Department of Physics, National Tsing Hua Univerisity, Hsinchu, Taiwan

* Presenter:Yen-Hsun Lin, email:f01222018@ntu.edu.tw

III-V InGaAs semiconductors have been in a wide variety of research fields and device applications. Studies of high mobility two-dimensional electron gas (2DEG) in InGaAs have focused on fundamental physics such as Rashba-type spin-orbit interaction, and also searching Majorana fermions with the combination of high-mobility 2DEG and adjacent superconducting thin films. InGaAs device applications include high-speed electronic devices for wireless telecommunications and short-wavelength infrared optoelectronic devices. Nonetheless, one major obstacle to realize high-performance InGaAs devices is the high interface trap density (D_it) at oxide/InGaAs interface, giving strong carrier scattering effect and high surface recombination velocity. Passivating InGaAs surface with low D_it is vital to preserve its high carrier mobility and high quantum efficiency for high-performance InGaAs devices. Studies on InGaAs surface passivation over the past decades have produced the D_it’s below 10¹² eV^-1cm^-2 from the mid-gap to conduction band, but not from the mid-gap to the valence band edge, where the D_it’s remain high of 10¹² or over 10¹³ eV^-1cm^-2.
In this work, by perfecting the InGaAs surface preparation and utilizing in-situ Y₂O₃ deposition, we have attained record-low D_it down to 3x10¹¹ eV^-1cm^-2 at the lower-half bandgap of InGaAs for the first time. Moreover, we have achieved high-temperature thermal stability up to 800^oC. These achievements have paved the way for solving fundamental problems in the III-V surface passivation. Moreover, they will lead to high-performance InGaAs devices for many fundamental physics studies and novel technologies.

Keywords: III-V semiconductors, device physics, passivation, interface trap density (D_it), in-situ