The invention relates to the technical field of
semiconductor, in particular to a normally-closed GaN-based
MOSFET structure with a high
threshold voltage and high conduction performance and a fabrication method thereof. The fabrication method of the normally-closed GaN-based
MOSFET structure with the high
threshold voltage and high conduction performance comprises the following steps of firstly,providing a required substrate, sequentially and epitaxially growing a stress buffer layer, a GaN buffer layer, an AIN
thin layer and an AlGaN
thin layer on the substrate, and reserving the AlN
thin layer and the AlGaN thin layer on a grid region by
etching to obtain a substrate for
epitaxy of a selection region; secondly, sequentially selecting a regional epitaxial GaN channel layer, a AIN
insertion layer and a AIGaN
barrier layer on the substrate to form a groove structure; and finally, depositing a grid
dielectric layer, covering grid
metal on a groove channel grid
dielectric layer, and covering two ends of the grid with
metal to form a source and a drain. By the fabrication method, the
threshold voltage and the grid region mobility can be effectively improved, the channel resistance isreduced, and the conduction performance of the GaN
MOSFET device is improved.