Investigation of crystalline orientation of III-nitride semiconductors grown on high-index and non-polar oriented GaAs substrates

本文研究了在不同取向的砷化镓衬底上生长半极性氮化物半导体。在第23财年，阐明了半极性InN在GaAs(113)A、(113)B和非极性(110)表面的生长，以及InN与GaAs之间的外延关系和抑制孪晶形成的机制。此外，对于第24财年，我们还研究了(112)A、(112)B、(114)A和(114)B等其他指数的GaAs衬底上的InN生长。因此，正如我们预期的那样，当生长温度较高时，InN的[0001]方向倾向于平行于GaAs的[111]方向。因此，通过选择衬底的折射率(取向)，我们成功地生长出了不同晶体取向的半极性InN。(例如，可以在(110)和(113)B衬底上分别生长{10-13}取向和{11-22}取向的InN。)此外，通过利用同极性和N极性Inn之间的热稳定性差异，以及在生长过程中向载气中引入少量氢，可以抑制生长晶体中的孪晶形成。

In this research, investigation of semi-polar nitride semiconductor growth on GaAs substrates with various orientations was carried out. For fiscal 23rd, growth of semi-polar InN on GaAs(113)A, (113)B and non-polar (110) surfaces, and epitaxial relationship between InN and GaAs and mechanism for suppression of twin crystal formation were clarified. Also, for fiscal 24th, InN growth on GaAs substrates of other indices such as (112)A, (112)B, (114)A and (114)B was studied.Consequently, as we expected, [0001] direction of InN tended to be parallel to [111] direction of GaAs when the growth temperature is relatively high. As a result, we succeeded to grow semi-polar InN of various crystal orientations by selecting the index (orientation) of GaAs substrate. (For example, {10-13}-oriented and {11-22}-oriented InN can be grown on GaAs(110) and (113)B, respectively.) Also, it is possible to suppress the twin crystal formation into the grown crystal by using the difference in thermal stability between In-polarity and N-polarity InN, and by the introduction of small amount of hydrogen into the carrier gas during the growth.