No abstract

No abstract

No abstract

A bimodal deposition scheme combining radiofrequency magnetron sputtering and plasma enhanced chemical vapour deposition (PECVD) is proposed as a means for improving the performance of GaN-based metal–oxide–semiconductor high-electron-mobility transistors (MOSHEMTs). High-density sputtered-SiO2 is utilized to reduce the gate leakage current and enhance the breakdown voltage while low-density PECVD-SiO2 is employed to buffer the sputtering damage and further increase the drain current by engineering the stress-induced-polarization. Thus-fabricated MOSHEMT exhibited a low leakage current of 4.21 × 10−9 A mm−1 and high breakdown voltage of 634 V for a gate–drain distance of 6 µm, demonstrating the promise of bimodal-SiO2 deposition scheme for the development of GaN-based MOSHEMTs for high-power application.

Selective-area growth (SAG) based on plasma-assisted molecular-beam epitaxy (PAMBE) was shown to facilitate improvement of Ohmic contacts and directcurrent (DC) characteristics for GaN-based field-effect transistors (FETs) over the widely accepted ion-implantation technique. Twofold improvements in breakdown voltage were also demonstrated for samples grown on both sapphire and silicon substrates. An AlGaN/GaN high-electron-mobility transistor (HEMT) fabricated with PAMBE-SAG exhibited a low specific contact resistivity of 5.86 9 10 À7 X cm 2 , peak drain current of 420 mA/mm, and high breakdown voltage of 77 V. These results demonstrate that PAMBE-SAG is suited to fabricating HEMTs for high-power applications.

Selective area growth (SAG) based on plasma assisted molecular beam epitaxy (PAMBE) was demonstrated to be effective to achieve low contact resistance for nonalloyed ohmic metals. An AlGaN/GaN high‐electron mobility transistor (HEMT) using SAG by PAMBE with nonalloyed ohmic metals and recessed drain/source structure exhibited a low specific contact resistance of 3.7 × 10−5 Ω cm2, high‐peak drain current of 604 mA/mm, and small gate leakage current of 3.4 µA. These results demonstrate that SAG by PAMBE produces nonalloyed HEMT with comparable or more favorable electric performance versus conventional alloyed counterpart while avoiding problems of the latter resulting from high‐temperature annealing.

No abstract

No abstract