title: Plasma-assisted Molecular Beam Epitaxy of N-polar InAlN-barrier High-electron-mobility Transistors.
abstract: Plasma-assisted molecular beam epitaxy is well suited for the epitaxial growth of III-nitride thin films and heterostructures with smooth, abrupt interfaces required for high-quality high-electron-mobility transistors (HEMTs). A procedure is presented for the growth of N-polar InAlN HEMTs, including wafer preparation and growth of buffer layers, the InAlN barrier layer, AlN and GaN interlayers and the GaN channel. Critical issues at each step of the process are identified, such as avoiding Ga accumulation in the GaN buffer, the role of temperature on InAlN compositional homogeneity, and the use of Ga flux during the AlN interlayer and the interrupt prior to GaN channel growth. Compositionally homogeneous N-polar InAlN thin films are demonstrated with surface root-mean-squared roughness as low as 0.19 nm and InAlN-based HEMT structures are reported having mobility as high as 1,750 cm2/V∙sec for devices with a sheet charge density of 1.7 x 1013cm-2.
authors.affiliation: NRC Postdoctoral Scholar, Naval Research Laboratory; matthew.hardy.ctr@nrl.navy.mil.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Hardy
authors.affiliation: Electronics Science and Technology Division, Naval Research Laboratory.
authors.forename: David F
authors.initials: DF
authors.lastname: Storm
authors.affiliation: Electronics Science and Technology Division, Naval Research Laboratory.
authors.forename: D Scott
authors.initials: DS
authors.lastname: Katzer
authors.affiliation: Electronics Science and Technology Division, Naval Research Laboratory.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Downey
authors.affiliation: Electronics Science and Technology Division, Naval Research Laboratory.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Nepal
authors.affiliation: Electronics Science and Technology Division, Naval Research Laboratory.
authors.forename: David J
authors.initials: DJ
authors.lastname: Meyer
mesh_terms: D004583:Electrons; D014173:Transistors, Electronic