Normally-Off GaN-on-Si MISFET Using PECVD SiON Gate Dielectric

Abstract

We have developed a silicon oxynitride (SiON) deposition process using a plasma-enhanced chemical vapor deposition system for the gate dielectric of GaN-on-Si metal-insulator-semiconductor field-effect transistors (MISFETs). The optimized SiON film had a relative dielectric constant of 5.3 and a breakdown field of 12 MV/cm. A normally-off GaN-on-Si MISFET fabricated with a 33-nm SiON gate dielectric exhibited a threshold voltage of ~2 V, an ON-resistance of 7.85 mQ · cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , and a breakdown voltage of ~640 V at the OFF-state current density of 1 μA/mm. The extracted interface trap density was 1 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> · eV <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> at E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> - E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> = 0.442 eV, which resulted in negligible hysteresis and excellent dynamic characteristics.