[paper] Fabrication EM AlGaN/GaN MIS HEMT

Flavien Cozette¹, Bilal Hassan¹, Christophe Rodriguez¹, Eric Frayssinet², Rémi Comyn², François Lecourt³, Nicolas Defrance⁴, Nathalie Labat⁵, François Boone¹, Ali Soltani¹, Abdelatif Jaouad¹, Yvon Cordier² and Hassan Maher¹

New barrier layer design for the fabrication of gallium nitride-metal-insulator-semiconductor-high electron mobility transistor normally-off transistor

2021 Semicond. Sci. Technol. 36 034002

DOI: 10.1088/1361-6641/abd489

¹LN2, CNRS-UMI-3463, 3IT, Université de Sherbrooke, Canada

²Université Côte d'Azur, CNRS, CRHEA, Valbonne, France

³OMMIC, 94450 Limeil-Brévannes, France

⁴IEMN, CNRS-UMR-8520, University of Lille, France

⁵IMS, CNRS-UMR-5218, University of Bordeaux, France

Abstract: This paper reports on the fabrication of an enhancement-mode AlGaN/GaN metal-insulator-semiconductor-high electron mobility transistor with a new barrier epi-layer design based on double Al0.2Ga0.8N barrier layers separated by a thin GaN layer. Normally-off transistors are achieved with good performances by using digital etching (DE) process for the gate recess. The gate insulator is deposited using two technics: plasma enhance chemical vapour deposition (sample A) and atomic layer deposition (sample B). Indeed, the two devices present a threshold voltage (Vth) of +0.4 V and +0.9 V respectively with ΔVth about 0.1 V and 0.05 V extracted from the hysteresis gate capacitance measurement, a gate leakage current below 2 × 10−10 A mm−1, an ION/IOFF about 108 and a breakdown voltage of VBR = 150 V and 200 V respectively with 1.5 µm thick buffer layer. All these results are indicating a good barrier surface quality after the gate recess. The DE mechanism is based on chemical dissolution of oxides formed during the first step of DE. Consequently, the process is relatively soft with very low induced physical damages at the barrier layer surface.

Fig: SEM image of an E-mode device.

Acknowledgments: This work was supported by Fonds de Recherches du Québec—Nature, Technologies (FRQNT), the Natural Sciences and Engineering Research Council of Canada (NSERC), French technology facility network RENATECH and the French National Research Agency (ANR) through the projects ED-GaN (ANR-16-CE24-0026-02) and the 'Investissements d'Avenir' program GaNeX (ANR-11-LABX-0014).