High-Performance InAlN/GaN MOSHEMTs Enabled by Atomic Layer Epitaxy MgCaO as Gate Dielectric

• Published in: IEEE electron device letters 2016-05, Vol.37 (5), p.556-559
• Main Authors: Hong Zhou, Xiabing Lou, Conrad, Nathan J., Mengwei Si, Heng Wu, Alghamdi, Sami, Shiping Guo, Gordon, Roy G., Ye, Peide D.
• Format: Article
• Language: English
• Subjects: ALE; Aluminum oxide; Capacitance-voltage characteristics; Epitaxial growth; epitaxial oxide; Gallium nitride; HEMTs; InAlN/GaN; Logic gates; MODFETs; MOSHEMT; solar (photovoltaic), solar (fuels), solid state lighting, phonons, thermoelectric, hydrogen and fuel cells, defects, charge transport, optics, materials and chemistry by design, synthesis (novel materials)
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2016.2537198

We have demonstrated high-performance InAlN/ GaN MOS high-electron-mobility-transistors (MOSHEMTs) with various channel lengths (L ch ) of 85-250 nm using atomic-layer-epitaxy (ALE) crystalline Mg 0.25 Ca 0.75 O as gate dielectric. With a nearly lattice matched epitaxial oxide, the interface between oxide and barrier is improved. The gate leakage current of MOSHEMT is reduced by six orders of magnitude compared with HEMT. An OFF-state leakage current of 3 × 10 -13 A/mm, ON/OFF ratio of 4 × 10 12 , almost ideal subthreshold swing of 62 mV/decade, low drain current noise with Hooge parameter of 10 -4 , and negligible current collapse and hysteresis are realized. The 85-nm Lch MOSHEMT also exhibits good ON-state performance with I dmax = 2.25 A/mm, R ON = 1.3 Ω · mm, and g max = 475 mS/mm, showing that ALE MgCaO is a promising gate dielectric for GaN device applications.