Role of the dielectric for the charging dynamics of the dielectric/barrier interface in AlGaN/GaN based metal-insulator-semiconductor structures under forward gate bias stress
- Infineon Technologies Austria AG, Siemensstraße 2, 9500 Villach (Austria)
- Fraunhofer IPMS-CNT, Königsbrücker Straße 178, 01099 Dresden (Germany)
- Institute of Solid State Electronics, Vienna University of Technology, Floragasse 7, 1040 Wien (Austria)
The high density of defect states at the dielectric/III-N interface in GaN based metal-insulator-semiconductor structures causes tremendous threshold voltage drifts, ΔV{sub th}, under forward gate bias conditions. A comprehensive study on different dielectric materials, as well as varying dielectric thickness t{sub D} and barrier thickness t{sub B}, is performed using capacitance-voltage analysis. It is revealed that the density of trapped electrons, ΔN{sub it}, scales with the dielectric capacitance under spill-over conditions, i.e., the accumulation of a second electron channel at the dielectric/AlGaN barrier interface. Hence, the density of trapped electrons is defined by the charging of the dielectric capacitance. The scaling behavior of ΔN{sub it} is explained universally by the density of accumulated electrons at the dielectric/III-N interface under spill-over conditions. We conclude that the overall density of interface defects is higher than what can be electrically measured, due to limits set by dielectric breakdown. These findings have a significant impact on the correct interpretation of threshold voltage drift data and are of relevance for the development of normally off and normally on III-N/GaN high electron mobility transistors with gate insulation.
- OSTI ID:
- 22311357
- Journal Information:
- Applied Physics Letters, Vol. 105, Issue 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
Similar Records
Impact of GaN cap on charges in Al₂O₃/(GaN/)AlGaN/GaN metal-oxide-semiconductor heterostructures analyzed by means of capacitance measurements and simulations
Investigating compositional effects of atomic layer deposition ternary dielectric Ti-Al-O on metal-insulator-semiconductor heterojunction capacitor structure for gate insulation of InAlN/GaN and AlGaN/GaN