Assessment of the pendeo‐epitaxy effect on 2DEG mobility in III‐nitride HEMT heterostructures

Abstract

We have analyzed theoretically the electron scattering related to the interface roughness produced by threading dislocations in the channel of an AlGaN/GaN HEMT heterostructure. On the basis of the analysis, we predict the use of the pendeo‐epitaxy for growing the transistor structure to improve the low‐temperature and roomtemperature mobility of two‐dimensional electrons by ∼80% and ∼28%, respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Very high channel conductivity in low-defect AlN/GaN high electron mobility transistor structures

“…Though the Coulomb scattering of 2DEG from the charged dislocation lines is expected to be well screened for n s Ͼ 10 12 cm −2 , a large density of TDs can still reduce the mobility by scattering due to both strain variations across the interface, which results in a nonuniform polarization field, and increased surface roughness ͑e.g., by hillock formation͒. 17 This is also indicated in recent calculations of Bulashevich et al 18 showing the effect of the interface rms roughness, ⌬ resulting from TDs at a density of N TD , on the low-temperature mobility as −1 ϰ⌬ 2 ͑n s N TD ͒ 1/2 . Finally, a comparison of samples 2 and 6 in Table I shows that to a lesser extent the thickness of the GaN cap layer can also affect n s which could be caused by modifying the strain and/or the density of surface states.…”

Improved performance of Schottky diodes on pendeoepitaxial gallium nitride

“…͓DOI: 10.1063/1.2978404͔ Gallium nitride is a wide bandgap semiconductor having superior material characteristics for numerous electronic applications, compared to commonly used semiconductors such as Si and GaAs. 7 From the modeling results, it was estimated that the use of pendeoepitaxy will improve the low temperature and room temperature mobility of the two dimensional electron gas electrons in the HEMT by approximately 80% and 28%, respectively. 1 However, long term device reliability is currently a critical issue that must be solved to enable the insertion of GaN devices and integrated circuits into systems.…”