Improved hysteresis in a normally-off AlGaN/GaN MOS heterojunction field-effect transistor with a recessed gate structure formed by selective regrowth

Abstract

A normally-off AlGaN/GaN MOS heterojunction field-effect transistor (MOS-HFET) with a recessed gate structure formed by selective area regrowth is demonstrated. The fabricated MOS-HFET exhibits a threshold voltage of 1.7 V with an improved hysteresis of 0.5 V as compared with a device fabricated by a conventional dry etching process. An analysis of capacitance–voltage (C–V) characteristics reveals that the dry etching process increases interface state density and introduces an additional discrete trap. The use of the selective area regrowth technique effectively suppresses such degradation, avoiding the MOS interface from being exposed to dry etching. The results presented in this paper indicate that the selective area regrowth technique is promising for the fabrication of normally-off AlGaN/GaN MOS-HFETs.

InGaN/(GaN)/AlGaN/GaN normally-off metal-oxide-semiconductor high-electron mobility transistors with etched access region

“…A particularly large I DS hysteresis and V T ∼ 0 V was observed after the etching, which was the HEMT initial vital stage, after only marginal current of the virgin (un-etched) device. Large hysteresis is often a consequence of deep levels and trapping in the MOS gate stack, particularly in normally-off HEMTs, 25,26) and increases with applied V GS . [27][28][29] After the passivation hysteresis was largely eliminated, most likely because of decreased V T and low V GS of the normally-on operation.…”

High quality nitride semiconductors grown on novel ScAlMgO4 substrates and their light emitting diodes

“…The V/III ratio was kept constant and was 2790. In order to evaluate the crystallinity of the grown film, X-ray rocking curves of (0002) plane and (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) plane were measured. Cathode luminescence (CL) method at RT was used for evaluation of dislocation density of the grown film.…”

“…2, an improvement of the FWHM values of the (0002) plane was observed with increasing growth rate. On the other hand, the FWHM values of the asymmetric (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) plane was deteriorated at 3 μm h −1 or more. The behavior of X-ray rocking curves for these growth rates is not the specificity in GaN growth on SCAMO, and a similar trend was also observed in GaN growth on sapphire.…”

“…Group-III nitride semiconductors have attracted much attention for their use in optoelectronic devices, such as laser diodes (LDs), [1][2][3] LEDs [4][5][6] and FETs. [7][8][9][10][11][12][13] In general, most of the III-N semiconductor devices have been fabricated on sapphire substrates. However, a large lattice mismatch as large as 15% between GaN and sapphire induces high density dislocations in III-N semiconductors grown on sapphire.…”

Fabrication of Low On‐Resistance and Normally Off AlGaN/GaN Metal Oxide Semiconductor Heterojunction Field‐Effect Transistors with AlGaN Back Barrier by the Selective Area Regrowth Technique

“…[9,10,13] Another approach to achieve normally off devices is a selective area regrowth (SAG) technique to enable the formation of the recessed-gate structure without dry etching. [14][15][16][17] Our group recently reported the fabrication of recessed-gate MOSFET without degradation of a gate stack by SAG. [18] It was also found that surface treatment of a GaN template before regrowth is important for improving the electrical properties of AlGaN/GaN heterostructure.…”