@article{dang_gudipati_liu_li_liu_peterson_chisholm_biggerstaff_duscher_wang_2009, title={Carbon Clusters as Possible Defects in the SiC-SiO2 Interface}, volume={6}, ISSN={["1546-1963"]}, DOI={10.1166/jctn.2009.1179}, abstractNote={High state densities in the band gap of the SiC-SiO2 interface significantly reduce the channel mobilities in SiC-based high-temperature/high-power microelectronics. Investigations of the nature of the interface defects are thus of great importance. While several possible defects including very small carbon clusters with up to four carbon atoms have been identified by first-principles theory, larger carbon clusters as possible defects have attracted less attention. Here, we report first-principles quantum-mechanical calculations for two larger carbon clusters, the C10 ring and the C20 fullerence, in the SiC-SiO2 interface. We find that both carbon clusters introduce significant states in the band gap. The states extend over the entire band gap with higher densities in the upper half of the gap, thus accounting for some of the interface trap densities observed experimentally}, number={6}, journal={JOURNAL OF COMPUTATIONAL AND THEORETICAL NANOSCIENCE}, author={Dang, Hongli and Gudipati, Ramkumar and Liu, Yang and Li, Ying and Liu, Yingdi and Peterson, Heather L. and Chisholm, Matthew F. and Biggerstaff, Trinity and Duscher, Gerd and Wang, Sanwu}, year={2009}, month={Jun}, pages={1305–1310} }
 @article{biggerstaff_reynolds_zheleva_lelis_habersat_haney_ryu_agarwal_duscher_2009, title={Relationship between 4H-SiC/SiO2 transition layer thickness and mobility}, volume={95}, ISSN={["0003-6951"]}, DOI={10.1063/1.3144272}, abstractNote={The interfacial region between silicon carbide (SiC) and its native oxide contains a high density of interfacial traps, which is considered a major problem leading to a lower mobility that has hindered SiC metal oxide semiconductor field effect transistors from reaching their theoretical expectations. We investigate the microstructure and chemistry of the 4H-SiC∕SiO2 interface due to variations in nitric oxide annealing and aluminum implantation using Z-contrast imaging and electron energy loss spectroscopy. A transition layer with a carbon to silicon ratio greater than 1 is consistently observed on the SiC side of the interface in each of these samples, and the width of this transition layer is found to be inversely related to the effective channel mobility measured on fabricated devices.}, number={3}, journal={APPLIED PHYSICS LETTERS}, author={Biggerstaff, T. L. and Reynolds, C. L., Jr. and Zheleva, T. and Lelis, A. and Habersat, D. and Haney, S. and Ryu, S. -H. and Agarwal, A. and Duscher, G.}, year={2009}, month={Jul} }
 @article{saripalli_pei_biggerstaff_ramachandran_duscher_johnson_zeng_dandu_jin_barlage_2007, title={Transmission electron microscopy studies of regrown GaN Ohmic contacts on patterned substrates for metal oxide semiconductor field effect transistor applications}, volume={90}, ISSN={["1077-3118"]}, DOI={10.1063/1.2741123}, abstractNote={Contact selected area regrowth of GaN was performed by metal organic chemical vapor deposition using a silicon nitride dielectric hard mask to define plasma etched recesses and to define source-drain regions. A low temperature regrowth process at 750–850°C was adopted to limit lateral overgrowth. High resolution electron microscopy images and selected area diffraction confirmed the regrowth selectivity and revealed that the low temperature regrown GaN is epitaxial and has a wurtzite crystal structure. I-V characteristics of the fabricated metal oxidesemiconductor field effect transistor show enhancement mode operation.}, number={20}, journal={APPLIED PHYSICS LETTERS}, author={Saripalli, Y. N. and Pei, L. and Biggerstaff, T. and Ramachandran, S. and Duscher, G. J. and Johnson, M. A. L. and Zeng, C. and Dandu, K. and Jin, Y. and Barlage, D. W.}, year={2007}, month={May} }