β-Ga2O3 MOSFETs electrical characteristic study of various etching depths grown on sapphire substrate by MOCVD

Abstract

Abstractβ-Ga2O3 thin films with both a 45 nm Si-doped conductive epilayer and unintentionally doped epilayer were grown on c-plane sapphire substrate by metalorganic chemical vapor deposition. β-Ga2O3 based metal–oxide–semiconductor field-effect transistors (MOSFETs) were fabricated with gate recess depths of 20 nm and 40 nm (it indicated gate depth with 70 nm and 50 nm, respective), respectively, and without said recessing process. The conductivity of β-Ga2O3 epilayers was improved through low in situ doping using a tetraethoxysilane precursor to increase MOSFET forward current density. After recessing, MOSFET operation was transferred from depletion to enhanced mode. In this study, the maximum breakdown voltage of the recessed 40 nm transistor was 770 V. The etching depth of a recessed-gate device demonstrates its influence on device electrical performance.

Undoped β-Ga2O3 Layer Thickness Effect on the Performance of MOSFETs Grown on a Sapphire Substrate

“…First, films with different UID layer thicknesses were analyzed by transmission line measurement (TLM) to determine the ohmic-contact properties and resistance between S and D electrodes for n + Si-doped Ga 2 O 3 epilayers. The sheet resistance ( R S ), transfer length ( L T ), and specific contact resistance (ρ c ) can be obtained using the TLM measurement. , The L T of UID layer thicknesses of 50, 100, and 200 nm were 1.02, 0.69, and 0.83 μm, respectively. R S was found to be 21.87, 13.76, 8.76 kΩ/sq, and ρ c were 21.87, 6.32, and 5.97 mΩ/mm 2 , respectively.…”

“…The sheet resistance (R S ), transfer length (L T ), and specific contact resistance (ρ c ) can be obtained using the TLM measurement. 28,29 The L T of UID layer thicknesses of 50, 100, and 200 nm were 1.02, 0.69, and 0.83 μm, respectively. R S was found to be 21.87, 13.76, 8.76 kΩ/sq, and ρ c were 21.87, 6.32, and 5.97 mΩ/mm 2 , respectively.…”