ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Silicon has been the semiconductor of choice for microelectronics largely because of theunique properties of its native oxide (SiO2) and the Si/SiO2 interface. For high-temperature and/orhigh-power applications, however, one needs a semiconductor with a wider energy gap and higherthermal conductivity. Silicon carbide has the right properties and the same native oxide as Si. However,in the late 1990’s it was found that the SiC/SiO2 interface had high interface trap densities, resultingin poor electron mobilities. Annealing in hydrogen, which is key to the quality of Si/SiO2interfaces, proved ineffective. This paper presents a synthesis of theoretical and experimental workby the authors in the last six years and parallel work in the literature. High-quality SiC/SiO2 interfaceswere achieved by annealing in NO gas and monatomic H. The key elements that lead to highqualitySi/SiO2 interfaces and low-quality SiC/SiO2 interfaces are identified and the role of N and Htreatments is described. More specifically, optimal Si and SiC surfaces for oxidation are identifiedand the atomic-scale processes of oxidation and resulting interface defects are described. In the caseof SiC, we conclude that excess carbon at the SiC/SiO2 interface leads to a bonded Si-C-O interlayerwith a mix of fourfold- and threefold-coordinated C and Si atoms. The threefold coordinated atomsare responsible for the high interface trap density and can be eliminated either by H-passivation orreplacement by N. Residual Si-Si bonds, which are partially passivated by H and N remain the mainlimitation. Perspectives for the future for both Si- and SiC-based MOSFETs are discussed
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/13/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.527-529.935.pdf
