Fully Ion Implanted Normally-Off GaN DMOSFETs with ALD-Al?O? Gate Dielectrics.

ABSTRACT: A normally-off GaN double-implanted vertical MOSFET (DMOSFET) with an atomic layer deposition (ALD)-Al?O? gate dielectric film on a free-standing GaN substrate fabricated by triple ion implantation is presented. The DMOSFET was formed with Si ion implanted source regions in a Mg ion implanted p-type base with N ion implanted termination regions. A maximum drain current of 115 mA/mm, maximum transconductance of 19 mS/mm at a drain voltage of 15 V, and a threshold voltage of 3.6 V were obtained for the fabricated DMOSFET with a gate length of 0.4 ?m with an estimated p-type base Mg surface concentration of 5 × 1018 cm-3. The difference between calculated and measured Vths could be due to the activation ratio of ion-implanted Mg as well as Fermi level pinning and the interface state density. On-resistance of 9.3 m?·cm² estimated from the linear region was also attained. Blocking voltage at off-state was 213 V. The fully ion implanted GaN DMOSFET is a promising candidate for future high-voltage and high-power applications.

SUBMITTER: Yoshino M 

PROVIDER: S-EPMC6427114 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature