GaN과 Ge 기판을 이용한 MOS 소자의 전기적 특성 연구

Abstract

ABSTRACT

Electrical characterization of GaN and Ge MOS Device

WOOSUK JUNG Dept. of Mat. Sci. & Eng. The Graduated School Hanyang University

The effects of NH3 plasma passivation in order to improve Electrical and interface properties on GaN metal oxide semiconductor (MOS) device were investigated using thermal ALD HfO2 gate dielectrics. Comparing with “No plasma” and “NH3 plasma 50 W for 5, 10, 15 minutes” with diluted HCl (H2O/HCl =1:1, 10 minutes) clean, NH3 plasma 50 W, 10 minutes condition was the best in improving Electrical and interface properties. Namely, very small frequency dispersion 2.2 % in the accumulation region, a negligible hysteresis ~10 mV at 1 MHz, a lower leakage current density 6.36 x 10-2 A/cm2 at VFB + 0.5 V and a low interface trap density (Dit) ~6 x 1011 eV-1•cm-2 at Ec - Et = 0.29 eV, respectively. Because NH3 plasma passivation which can effectively remove carbon contamination and passivate the surface and bulk defects on GaN. Besides, it has additional H+ passivation effect after N2 and H2 dissociation under low plasma power in NH3. The Ge MOS devices of 2nm ZnO passivation between HfO2 and Ge show improved electrical properties such as frequency dispersion in the depletion region, accumulation capacitance. ultrathin ZnO (~2nm) passivation can effectively suppress interfacial layer between Hf and Ge. due to transition metal as Hf, Ti, Zr, V has negative gibbs free energy which tend to form metal oxide. Also, significant suppression of GeOX formation which reduces device performance on Ge through in situ ALD HfO2/ZnO deposition without air break.