Quality and reliability of in-situ Al2O3 MOS capacitors for GaN-based power devices

Abstract

This work reports on the electrical characterization of Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /GaN MOS capacitors grown by means of metal-organic chemical vapor deposition. Novel results for 25-nm-thick Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> show (i) an interface-state density measured by means of UV-assisted C-V technique lower than 7x10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> ; (ii) flat-band voltage shift lower than 100 mV up to a gate voltage of 4 V (1.6 MV/cm); (iii) a breakdown strength of 8.8 MV/cm; (iv) timeto-breakdown of 20 years for electric field smaller than 3.7 MV/cm at room temperature, and charge to breakdown of 13.6 C/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> if measured at 10 mA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> with an electric field of ~5.6 MV/cm.