Characteristics of 4H–SiC MOS interface annealed in N2O

• Published in: Solid-state electronics Vol. 49; no. 6; pp. 896 - 901
• Main Authors: Fujihira, Keiko, Tarui, Yoichiro, Imaizumi, Masayuki, Ohtsuka, Ken-ichi, Takami, Tetsuya, Shiramizu, Tatsuya, Kawase, Kazumasa, Tanimura, Jyunji, Ozeki, Tatsuo
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.06.2005; Elsevier Science
• Subjects: Applied sciences; Channel mobility; Compound structure devices; Electronics; Exact sciences and technology; Interface state density; MOSFET; Nitridation; Oxidation; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Silicon carbide; Transistors; Channel mobility; MOSFET; Oxidation; Silicon carbide; Interface state density; Nitridation; Voltage threshold; Interface state; Density of states; Annealing; Charge carrier mobility; Temperature effect; MOS structure; n channel; Nitriding; Controlled atmosphere; n type semiconductor; Voltage capacity curve; Planar technology
• ISSN: 0038-1101; 1879-2405
• DOI: 10.1016/j.sse.2004.10.016

4H–SiC(0001) MOSFET annealed in N2O at below 1150°C is systematically investigated. Inversion-type planar MOSFETs show higher channel mobility and lower threshold voltage by increasing anneal temperature. Through C–V measurement of n-type MOS capacitors, the interface state density is revealed to decrease at higher anneal temperature. The field effect mobility of 30cm2/Vs is achieved by 1150°C anneal for 3h, which is about 10 times higher than that of not annealed MOSFET. Epitaxial n-channel MOSFET annealed in N2O has been also fabricated. A positive threshold voltage of 0.46V and the field effect mobility of 45cm2/Vs are attained. The effective mobility at 2.5MV/cm is 34cm2/Vs, which is five times higher than that for not annealed sample, suggesting that the N2O anneal improves the MOS interface quality.