LP MOCVD growth of InAlN/GaN HEMT heterostructure: comparison of sapphire, bulk SiC and composite SiCopSiC substrates for HEMT device applications

Abstract

In this paper we report on low‐pressure metalorganic vapour deposition of InAlN/GaN heterostructures grown on different substrates (Sapphire, bulk SiC, composite SiCopSiC) for HEMT applications, and on first device performances obtained with these heterostructures. Optimisation of the crystal growth on each kind of substrate has led to InAlN/GaN HEMT heterostructures grown on bulk SiC and on composite SiCopSiC substrates which are successfully compared, in terms of material quality, to the standard GaAlN/GaN HEMT heterostructures grown on bulk SiC substrates. First devices based on InAlN/GaN heterostructures grown on bulk SiC exhibit very good microwave performances, with output power of 10.3 W/mm at 10 GHz, similar to those obtained with GaAlN/GaN heterostructures, confirming the promising potential of InAlN material. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

High electron mobility in high-polarization sub-10 nm barrier thickness InAlGaN/GaN heterostructure

“…4, state-of-the-art electron mobilities of 1800 cm 2 V −1 s −1 at RT and 6800 cm 2 V −1 s −1 at 77 K for a sheet carrier density of 1.9 × 10 13 cm −2 were measured, resulting in sheet resistances of 191 Ω=□ at RT and below 50 Ω=□ at 77 K. A real breakthrough in terms of electrical and structural properties of the SiN=InAlGaN=AlN=GaN heterojunction has been obtained, as compared with the InAlN=AlN=GaN heterojunction (typical values of μ 300K are about 1300 m 2 V −1 s −1 for 1.3 × 10 13 cm −2 ). 11) This result is in good agreement with those shown in a number of papers independently reporting higher mobilities in quaternary barrier InAlGaN HEMTs than in ternary InAlN HEMTs with similar designs. [5][6][7] Nevertheless, optimizations of the thickness and growth conditions of the AlN spacer are still crucial to achieve such high mobilities in In-containing III-N HEMT structures.…”

“…Details on the growth of III-N HEMT structures with Incontaining barrier layers nearly lattice matched to GaN may be found elsewhere. [10][11][12] The main physical properties of the Si x N y =InAlGaN=AlN=GaN HEMT heterostructure were checked using nondestructive characterization techniques such as high-resolution X-ray diffraction, Hg probe capacitance-voltage (C-V ) measurements, eddy current probe (Lehighton) measurements, optical microscopy, and AFM. The above-mentioned HEMT heterostructure grown under optimized growth parameters presents a "mirrorlike" surface morphology, as confirmed by AFM analysis (Fig.…”

Low resistive Au-free, Ta-based, recessed ohmic contacts to InAlN/AlN/GaN heterostructures

“…The thickness uniformity of the epi-structure was 1.9%. Details on the growth of InAlN/AlN/GaN HEMT structures may be found in [23].…”

Evaluation of Thermal Versus Plasma-Assisted ALD Al₂O₃ as Passivation for InAlN/AlN/GaN HEMTs

“…Ta-based ohmic contacts were deposited and annealed at low temperature. More information on the growth and the processing can be found in [6]- [8]. The substrate was split into three pieces which were passivated individually.…”