High Performance and Highly Robust AlN/GaN HEMTs for Millimeter-Wave Operation

Kathia Harrouche,Etienne Okada,Farid Medjdoub,Riad Kabouche

doi:10.1109/jeds.2019.2952314

Abstract

We report on a 3 nm AlN/GaN HEMT technology for millimeter-wave applications. Electrical characteristics for a 110 nm gate length show a maximum drain current density of 1.2 A/mm, an excellent electron confinement with a low leakage current below 10 μA/mm, a high breakdown voltage and a FT/Fmax of 63/300 GHz at a drain voltage of 20V. Despite residual trapping effects, state of the art large signal characteristics at 40 GHz and 94 GHz are achieved. For instance, an outstanding power added efficiency of 65% has been reached at VDS = 10V in pulsed mode at 40 GHz. Also, an output power density of 8.3 W/mm at VDS = 40V is obtained associated to a power added efficiency of 50%. At 94 GHz, a record CW output power density for Ga-polar GaN transistors has been reached with 4 W/mm. Additionally, room temperature preliminary robustness assessment at 40 GHz has been performed at VDS = 20V. 24 hours RF monitoring showed no degradation during and after the test.

Highlights

Gallium Nitride (GaN)-based RF power devices have made substantial progress in the last decade, which will enable new applications such as military wireless communication, SATCOM and 5G generation of mobile broadband
We have previously demonstrated the interest of the AlN/GaN heterostructure for mmW applications including the use of an ultrathin 4.0 nm barrier combined with an optimized Carbon-doped buffer [17]
We report on a further scaled 3.0 nm barrier AlN/GaN High Electron Mobility Transistors (HEMT) power performance up to the W-Band

Summary

INTRODUCTION

Gallium Nitride (GaN)-based RF power devices have made substantial progress in the last decade, which will enable new applications such as military wireless communication, SATCOM and 5G generation of mobile broadband. Those applications operating at high frequency need compact systems, for which the poweradded-efficiency (PAE) is a critical parameter. High Electron Mobility Transistors (HEMT) on SiC have already demonstrated attractive efficiencies up to Ka-Band [1]–[5] but limited data have been reported so far in the QBand [6]–[8] and above [9]–[15]. We report on a further scaled 3.0 nm barrier AlN/GaN HEMTs power performance up to the W-Band. Besides the state-of-the-art performance, a preliminary large signal robustness assessment at 40 GHz on these mmW devices is demonstrated

DEVICE FABRICATION

SHORT TERM LARGE SIGNAL ROBUSTNESS ASSESSMENT

CONCLUSION