Normally-off AlGaN/GaN MOS-HEMT using ultra-thin Al_0.45 Ga_0.55N barrier layer

Ahmed Chakroun (1, 2) , Abdelatif Jaouad (1, 2) , Meriem Bouchilaoun , Osvaldo Arenas , Ali Soltani (3) , Hassan Maher (4, 1, 2)

1 LN2 - Laboratoire Nanotechnologies Nanosystèmes
2 3IT - Institut Interdisciplinaire d'Innovation Technologique [Sherbrooke]
3 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520
4 OMMIC

In this work, we report on the fabrication of a normally‐off AlGaN/GaN Metal–Oxide–Semiconductor High Electron Mobility Transistor (MOS‐HEMT) using an ultra‐thin Al0.45Ga0.55N barrier layer. The AlGaN barrier was thinned down to 1 nm using a digital etching process (Oxidation/Etching) and was followed by a PECVD deposition technique of a 7 nm thick SiOx layer used as gate insulator. Thanks to the thin AlGaN barrier layer (4 nm), only a few digital etching cycles are required to shift the threshold voltage toward positive values. The fabricated normally‐off device exhibits a pinch‐off voltage of +1.1 V, a maximum IDS current of 460 mA mm−1 at VGS = +5 V, an On‐state resistance (RON) of 7.8 Ω · mm and an ION/IOFF ratio higher than 109. Moreover, the pulsed IDS–VDS and capacitance–voltage (C–V) curves versus frequency confirm that there is no damage induced by the digital etching process.

Mots clés: AlGaN; digital etching; GaN; high electron mobility transistors; metal-oxide-semiconductor structures; passivation

Domaines: Sciences de l'ingénieur [physics]

Ahmed Chakroun, Abdelatif Jaouad, Meriem Bouchilaoun, Osvaldo Arenas, Ali Soltani, et al.. Normally-off AlGaN/GaN MOS-HEMT using ultra-thin Al_0.45 Ga_0.55N barrier layer. physica status solidi (a), 2017, 214 (8), ⟨10.1002/pssa.201600836⟩. ⟨hal-01914374⟩