Barrier-Layer Scaling of InAlN/GaN HEMTs

Abstract

We discuss the characteristics of In0.17Al0.83N/GaN High Electron Mobility Transistors (HEMTs) with barrier thicknesses between 33 nm and 3 nm, grown on sapphire substrates by MOCVD. The maximum drain current (at VG = +2.0 V) decreased with decreasing barrier thickness due to the gate forward drive limitation and residual surface depletion effect. Full pinch-off and low leakage is observed. Even with 3nm ultra thin barrier the heterostructure and contacts are thermally highly stable (up to 1000°C).

Testing the Temperature Limits of GaN-Based HEMT Devices

“…• C in hydrogen/nitrogen (H 2 /N 2 ) atmospheres [33]. In this paper, the temperature limit is thought to be reached by the alloy formation between the Pt Schottky metal and AlGaN semiconductor material, particularly Ga.…”

“…• C even with a 3-nm lattice-matched barrier tested under identical conditions as the one applied to the AlGaN/GaN HEMTs previously described, where the gate contact becomes ohmic [33].…”

Status of the Emerging InAlN/GaN Power HEMT Technology

“…In the case of InAlN the surface potential of as-grown heterostructures is pinned at a level of approx. 0.4 eV and the barrier layer thickness can be scaled well below 25 nm [16], enabling planar high aspect ratio devices with nm gate lengths. In Fig.…”

Millimeter-Wave GaN HEMT for Power Amplifier Applications

“…GaN HEMT has attracted much attention as a device of millimeter-wave power amplifiers because of its several merits such as high breakdown voltage and high drain current due to high sheet carrier density of 2 dimensional electron gas (2DEG) of more than 1×10 13 cm −2 . And AlGaN/GaN HEMTs have been developed and used as microwave power amplifiers of cellular base stations due to their high output power and high efficiency performance [2].…”

“…Therefore, larger band gap materials with lager polarization effect such as InAlN have been considered for use as the barrier layer for millimeter-wave operations [10], [11]. InAlN/GaN HEMT has a twice higher 2DEG density than AlGaN/GaN HEMT due to its larger conduction band discontinuity ∆Ec and stronger spontaneous polarization effect [12], [13]. In a short-channel device, a buffer leakage current should also be considered to suppress the poor pinched-off characteristics.…”