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Valence- and Conduction-Band Offsets for Atomic-Layer-Deposited Al2O3 on (010) (Al0.14Ga0.86)2O3.
- Source :
- Journal of Electronic Materials; Mar2019, Vol. 48 Issue 3, p1568-1573, 6p, 2 Diagrams, 1 Chart, 6 Graphs
- Publication Year :
- 2019
-
Abstract
- The wide-bandgap ternary (Al<subscript>x</subscript>Ga<subscript>1−x</subscript>)<subscript>2</subscript>O<subscript>3</subscript> forms a heterostructure system with Ga<subscript>2</subscript>O<subscript>3</subscript> that is attracting attention for modulation-doped field-effect transistors. The options for gate dielectric on (Al<subscript>x</subscript>Ga<subscript>1−x</subscript>)<subscript>2</subscript>O<subscript>3</subscript> are limited by the need for adequate band offsets at the heterointerface. Al<subscript>2</subscript>O<subscript>3</subscript> deposited by atomic layer deposition (ALD) is one option due to its large bandgap (6.9 eV). We measured the valence-band offset at the Al<subscript>2</subscript>O<subscript>3</subscript>/(Al<subscript>0.14</subscript>Ga<subscript>0.86</subscript>)<subscript>2</subscript>O<subscript>3</subscript> heterointerface using x-ray photoelectron spectroscopy (XPS). Al<subscript>2</subscript>O<subscript>3</subscript> was deposited by ALD onto single-crystal β-(Al<subscript>0.14</subscript>Ga<subscript>0.86</subscript>)<subscript>2</subscript>O<subscript>3</subscript> (bandgap 5.0 eV) grown by molecular beam epitaxy (MBE). The valence-band offset was determined to be 0.23 ± 0.04 eV (straddling gap, type I alignment) for ALD Al<subscript>2</subscript>O<subscript>3</subscript> on β-(Al<subscript>0.14</subscript>Ga<subscript>0.86</subscript>)<subscript>2</subscript>O<subscript>3</subscript>. The conduction-band offset was 1.67 ± 0.30 eV, providing good electron confinement. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 03615235
- Volume :
- 48
- Issue :
- 3
- Database :
- Complementary Index
- Journal :
- Journal of Electronic Materials
- Publication Type :
- Academic Journal
- Accession number :
- 134565247
- Full Text :
- https://doi.org/10.1007/s11664-018-06885-x