Optimization of low temperature surface treatment of GaAs crystal

Ultra shallow sidewall GaAs tunnel junctions prepared by low-temperature area-selective epitaxial re-growth method

“…Then, in order to obtain a high-quality sidewall surface before LT-ASR, an AsH 3 surface treatment was carried out in the MLE chamber just prior to the epitaxial regrowth. In this process, the SiN-patterned GaAs substrate was heated to 350 1C for 30 min in AsH 3 at a pressure of 1.1 Â 10 À1 Pa. As reported previously [4], it has been shown that the controlled surface stoichiometry resulting from the AsH 3 surface treatment reduces the nonstoichiometrically related defects at the re-grown interface. The LT-ASR of p + -GaAs was carried out at 290 1C using Bismethylcyclopentadienylberyllium [Be(MeCp) 2 ].…”

Be doping in molecular layer epitaxy of GaAs

“…The growth temperatures were 260-375 1C. The background pressure of the MLE chamber was better than 10 À7 Pa. A surface treatment was carried out in the MLE chamber at 350 1C for 30 min under AsH 3 pressure of 1.2 Â 10 À1 Pa just prior to epitaxial growth in order to obtain a highquality surface before epitaxy [7,8].…”

Sidewall GaAs tunnel junctions fabricated using molecular layer epitaxy

“…Through these windows, the GaAs sidewall mesa was formed to a depth of 60 or 120 nm using a H 2 SO 4 -based solution. To obtain a high-quality junction interface, an AsH 3 surface treatment [12,67] was performed in the growth chamber right before the epitaxial regrowth. In this process, the SiN x -patterned GaAs substrate was heated to 350 • C for 30 min under an AsH 3 pressure of 8 × 10 −2 Pa.…”

“…We conclude that a sufficient AsH 3 surface treatment with long t FD induces shallower deep levels, which will be followed by a less-strained atomic configuration around the defects. The control of surface stoichiometry by AsH 3 surface treatment has been reported to reduce the nonstoichiometry-related defects at the regrown interface [67]. Thus, the AsH 3 surface treatment reduces the density of deep levels at the sidewall tunnel junction interface, and the J v decreases, while the PVCR increases for longer t FD .…”