Growth model investigation for AlN/Al(Ga)InN interface growth by plasma-assisted molecular beam epitaxy for high electron mobility transistor applications

Abstract

Heterostructures with lattice matched Al(Ga)InN barriers have been widely investigated as alternative to standard AlGaN/GaN based high electron mobility transistor structures for high power applications. Mostly these heterostructures comprise a thin AlN based spacer between GaN channel and lattice matched barrier. One key issue for high quality plasma-assisted molecular beam epitaxy (PA-MBE) of these structures is the control of the AlN-Al(Ga)InN interface since optimal growth conditions for high quality AlN differ significantly from those for growth of indium containing material. In this paper, a detailed analysis and a deduced model of the interface growth is presented. The Al/N ratio during AlN spacer growth is likely to influence the subsequent growth of quaternary Al(Ga)InN. Ideal Al/N ratio leads to high performance heterostructures, while slightly Al-rich conditions lead to the formation of Al residues on the substrate surface, which hinder subsequent epitaxial growth. Al/N ratios below unity lead to the deposition of ternary AlGaN instead of binary AlN spacers and to increased alloy scattering. An insertion of a thin GaN layer between spacer and barrier can hinder the formation of Al residues and leads to improved wafer homogeneity

High-Current Submicrometer Tri-Gate GaN High-Electron Mobility Transistors With Binary and Quaternary Barriers

“…It has already been determined in an earlier study [5] that the use of quaternary layers bear great potential to enhance the performance of GaN HEMTs, having reached carrier mobilities over 1600 cm 2 /Vs. Experimental results in this work demonstrate very linear RF-and superior DC-performance of the proposed FinFETs with record current densities of ∼3.8 A/mm, which is more than double the value of conventional planar FETs.…”

“…In this letter, we adopt the lattice-matched InAlGaN and AlN-barrier layers [5]- [8] to improve the saturation drain current density and transconductance of Tri-gate [9]- [16] HEMTs, compared to the AlGaN. It has already been determined in an earlier study [5] that the use of quaternary layers bear great potential to enhance the performance of GaN HEMTs, having reached carrier mobilities over 1600 cm 2 /Vs.…”

Intramolecularly Stabilized o-Carboranyl Aluminum Complexes: Synthesis, Characterization, and X-ray Structural Studies

“…Recently, interest in aluminum nitride (AlN) [13], a form in which aluminum and nitrogen are combined, has been on the rise due to AlN being one of the few materials with both a wide direct bandgap and large thermal conductivity [14][15][16][17][18][19][20]. Group 13 metal nitrides are commonly used in optoelectronics [21][22][23][24][25][26], as well as in high-power and high-frequency electronics [27][28][29][30][31], owing to their small atomic mass, strong interatomic bonds, and simple crystal structure [32]. In particular, from among group 13 metal nitrides, AlN has the highest thermal conductivity and demonstrates the most effective dissipation of heat from a wide variety of power and radio frequency electronics [27][28][29][30][31].…”

“…Group 13 metal nitrides are commonly used in optoelectronics [21][22][23][24][25][26], as well as in high-power and high-frequency electronics [27][28][29][30][31], owing to their small atomic mass, strong interatomic bonds, and simple crystal structure [32]. In particular, from among group 13 metal nitrides, AlN has the highest thermal conductivity and demonstrates the most effective dissipation of heat from a wide variety of power and radio frequency electronics [27][28][29][30][31].…”

AlN/GaN HEMTs grown by MBE and MOCVD: Impact of Al distribution

“…x Al ≤ 30% to their limit. Therefore innovative barrier materials with an increased polarisation discontinuity, induced by high Al‐content, have been developed, such as (i) lattice matched In‐containing barriers or (ii) tensile strained AlN barriers . In case of binary AlN/GaN HEMTs, which allow the highest sheet carrier densities within the III‐nitrides, several promising results obtained by plasma‐assisted molecular beam epitaxy (PA‐MBE) growth on sapphire material have been reported .…”