Hydrogen in β-Ga2O3 passivates shallow impurities and deep-level defects and can have a strong effect on conductivity. More than a dozen O–D vibrational lines have been reported for β-Ga2O3 treated with the heavy isotope of hydrogen, deuterium. To explain the large number of O–D centers that have been observed, the involvement of additional nearby defects and impurities has been proposed. A few O–H centers have been associated with specific impurities that were introduced intentionally during crystal growth. However, definitive assignments of O–H and O–D vibrational lines associated with important adventitious impurities, such as Si and Fe, have been difficult. A set of well-characterized Si-doped β-Ga2O3 epitaxial layers with different layer thicknesses has been deuterated and investigated by vibrational spectroscopy to provide new evidence for the assignment of a line at 2577 cm−1 to an OD–Si complex. The vibrational properties of several of the reported OD-impurity complexes are consistent with the existence of a family of defects with a VGa1ic−D center at their core that is perturbed by a nearby impurity.
OH-Si complex in hydrogenated n-type β-Ga2O3:Si
Si is an n-type dopant in Ga2O3 that can be introduced intentionally or unintentionally. The results of Secondary Ion Mass Spectrometry, Hall effect, and infrared absorption experiments show that the hydrogen plasma exposure of Si-doped Ga2O3 leads to the formation of complexes containing Si and H and the passivation of n-type conductivity. The Si-H (D) complex gives rise to an O-H (D) vibrational line at 3477.6 (2577.8) cm-1 and is shown to contain a single H (or D) atom. The direction of the transition moment of this defect has been investigated to provide structure-sensitive information. Theory suggests possible structures for an OH-Si complex that are consistent with its observed vibrational properties.
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- Award ID(s):
- 1901563
- PAR ID:
- 10328661
- Date Published:
- Journal Name:
- Applied physics letters
- Volume:
- 119
- ISSN:
- 0003-6951
- Page Range / eLocation ID:
- 062109
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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