High electronic density is achieved by polarization doping without an impurity dopant in graded AlGaN films. Low specific contact resistance is studied on the polarization-doped AlGaN/GaN heterojunctions by using the transmission line method (TLM). The sheet density of polarization-doped AlGaN/GaN heterojunction is 6× 1014 cm-2 at room temperature. The linearly graded material structure is demonstrated by X-ray diffraction. The carrier concentration and mobility are characterized by a temperature-dependent Hall measurement. Multiple-layer metal (Ti/Al/Ti/Au) is deposited and annealed at 650 °C to realize the Ohmic contacts on the graded AlGaN/GaN heterojunctions.
|Journal||Chinese Physics B|
|State||Published - Oct 1 2014|
Bibliographical notePublisher Copyright:
© 2014 Chinese Physical Society and IOP Publishing Ltd.
- Ohmic contact
- carrier concentration
ASJC Scopus subject areas
- Physics and Astronomy (all)