@article{king_kern_benjamin_barnak_nemanich_davis_1999, title={Chemical vapor cleaning of 6H-SiC surfaces}, volume={146}, ISSN={["0013-4651"]}, DOI={10.1149/1.1392494}, abstractNote={The techniques (temperature range of study) of in situ thermal desorption (500-1100°C) and chemical vapor cleaning (CVC) via exposure to SiH 4 and/or C 2 H 4 (750-1100°C) have been investigated for preparing 6H SiC [(0001) Si , (0001) C , (1120), and (1010)] surfaces suitable for epitaxial growth of SiC and III-nitride films, and are compared with regard to surface purity, stoichiometry, and structural order. Oxide removal below the detection limits of Auger electron spectroscopy was achieved for all orientations via annealing in 200 L SiH 4 at 850-900°C or 200° lower than necessary by thermal desorption. No non-SiC carbon was detected on the surface by X-ray photoelectron spectroscopy. An approximately one-tenth of a monolayer of oxygen coverage and significant quantities of non-SiC carbon were detected for all 6H-SiC surfaces prepared by thermal desorption. In contrast to the predominantly non-SiC carbon-rich surfaces prepared by thermal desorption, the stoichiometry of the SiC surfaces prepared by CVC could be manipulated from Si-rich to C-rich without non-SiC carbon formation by either extending the SiH 4 exposures or by following with C 2 H 4 exposure. The latter surfaces also had lower concentrations of both oxygen and non-SiC carbon and increased surface order.}, number={9}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={King, SW and Kern, RS and Benjamin, MC and Barnak, JP and Nemanich, RJ and Davis, RF}, year={1999}, month={Sep}, pages={3448–3454} }
 @article{kern_rowland_tanaka_davis_1998, title={Aluminum nitride-silicon carbide solid solutions grown by plasma-assisted, gas-source molecular beam epitaxy}, volume={13}, ISSN={["0884-2914"]}, DOI={10.1557/JMR.1998.0257}, abstractNote={Solid solutions of aluminum nitride (AlN) and silicon carbide (SiC) have been grown at 900–1300 °C on vicinal α (6H)-SiC(0001) substrates by plasma-assisted, gas-source molecular beam epitaxy. Under specific processing conditions, films of (AlN)x(SiC) 1−x with 0.2 ≤ x ≤ 0.8, as determined by Auger electron spectrometry (AES), were deposited. Reflection high-energy electron diffraction (RHEED) was used to determine the crystalline quality, surface character, and epilayer polytype. Analysis of the resulting surfaces was also performed by scanning electron microscopy (SEM). High-resolution transmission electron microscopy (HRTEM) revealed that monocrystalline films with x ≥ 0.25 had the wurtzite (2H) crystal structure; however, films with x < 0.25 had the zincblende (3C) crystal structure.}, number={7}, journal={JOURNAL OF MATERIALS RESEARCH}, author={Kern, RS and Rowland, LB and Tanaka, S and Davis, RF}, year={1998}, month={Jul}, pages={1816–1822} }
 @article{jarrendahl_smith_zheleva_kern_davis_1998, title={Growth of highly (0001)-oriented aluminum nitride thin films with smooth surfaces on silicon carbide by gas-source molecular beam epitaxy}, volume={49}, ISSN={["0042-207X"]}, DOI={10.1016/S0042-207X(97)00177-2}, abstractNote={Aluminum nitride thin films with very smooth surfaces have been grown by gas-source molecular beam epitaxy on 4H and 6H silicon carbide substrates. High purity ammonia was used as the nitrogen source in conjunction with Al evaporated from an effusion cell. Streaked reflection high energy electron diffraction patterns and reconstructions of the AlN surfaces indicated smooth films. This surface character was confirmed via atomic force microscopy and transmission electron microscopy which showed roughness root mean square values typically below 1 nm and very flat surfaces, respectively. X-ray diffraction showed the films to be highly c-axis oriented and single phase. Major impurities in the AlN films were oxygen and carbon, as revealed by secondary ion mass spectrometry.}, number={3}, journal={VACUUM}, author={Jarrendahl, K and Smith, SA and Zheleva, T and Kern, RS and Davis, RF}, year={1998}, month={Mar}, pages={189–191} }
 @article{kern_tanaka_rowland_davis_1998, title={Reaction kinetics of silicon carbide deposition by gas-source molecular-beam epitaxy}, volume={183}, number={4}, journal={Journal of Crystal Growth}, author={Kern, R. S. and Tanaka, S. and Rowland, L. B. and Davis, R. F.}, year={1998}, pages={581–593} }
 @article{kern_davis_1997, title={Deposition and doping of silicon carbide by gas-source molecular beam epitaxy}, volume={71}, ISSN={["0003-6951"]}, DOI={10.1063/1.119892}, abstractNote={Thin films of silicon carbide (SiC) have been deposited at 1400–1450 °C on vicinal and on-axis 6H-SiC(0001) substrates by gas-source molecular beam epitaxy using the SiH4-C2H4-H2 gas system. Polytype control (6H- or 3C-SiC) was established by utilizing substrates of particular orientations. Residual, unintentionally incorporated nitrogen impurity levels were affected by changing the SiH4/C2H4 gas flow ratio, in agreement with the “site-competition epitaxy” model. In situ doping was achieved by intentional introduction of nitrogen and aluminum into the growing crystal.}, number={10}, journal={APPLIED PHYSICS LETTERS}, author={Kern, RS and Davis, RF}, year={1997}, month={Sep}, pages={1356–1358} }
 @article{davis_paisley_sitar_kester_ailey_linthicum_rowland_tanaka_kern_1997, title={Gas-source molecular beam epitaxy of III-V nitrides}, volume={178}, ISSN={["1873-5002"]}, DOI={10.1016/S0022-0248(97)00077-8}, abstractNote={Abstract Amorphous, hexagonal and cubic phases of BN were grown via ion beam assisted deposition on Si(1 0 0) substrates. Gas-source molecular beam epitaxy of the III–V nitrides is reviewed. Sapphire(0 0 0 1) is the most commonly employed substrate with 6H-SiC(0 0 0 1), ZnO(1 1 1) and Si(1 1 1) also being used primarily for the growth of wurtzite GaN(0 0 0 1) in tandem with previously deposited GaN(0 0 0 1) or AlN(0 0 0 1) buffer layers. Silicon(0 0 1), GaAs(0 0 1), GaP(0 0 1) and 3C-SiC(0 0 1) have been employed for growth of cubic (zincblende) β-GaN(0 0 1). The precursor materials are evaporated metals and reactive N species produced either via ECR or RF plasma decomposition of N2 or from ammonia. However, point defect damage from the plasma-derived species has resulted in a steady increase in the number of investigators now using ammonia. The growth temperatures for wurtzite GaN have increased from 650 ± 50°C to 800 ± 50°C to enhance the surface mobility of the reactants and, in turn, the efficiency of decomposition of ammonia and the microstructure and the growth rate of the films. Doping has been achieved primarily with Si (donor) and Mg (acceptor); the latter has been activated without post-growth annealing. Simple heterostructures, a p-n junction LED and a modulation-doped field-effect transistor have been achieved using GSMBE-grown material.}, number={1-2}, journal={JOURNAL OF CRYSTAL GROWTH}, author={Davis, RF and Paisley, MJ and Sitar, Z and Kester, DJ and Ailey, KS and Linthicum, K and Rowland, LB and Tanaka, S and Kern, RS}, year={1997}, month={Jun}, pages={87–101} }
 @article{kern_jarrendahl_tanaka_davis_1997, title={Growth and doping via gas-source molecular beam epitaxy of SiC and SiC/AlN heterostructures and their microstructural and electrical characterization}, volume={6}, ISSN={["0925-9635"]}, DOI={10.1016/S0925-9635(97)00066-6}, abstractNote={Gas-source molecular beam epitaxy has been employed to grown thin films of SiC and AlN on vicinal and on-axis 6H-SiC(0001). Growth using the SiH4C2H4 system resulted in 3C-SiC(111) epilayers under all conditions of reactant gas flow and temperatures. Films of 6H-SiC(0001) were deposited on vicinal 6H-SiC(0001) substrates using the SiH4C2H4H2 system at deposition temperatures ⩾ 1350°C. In situ doping was achieved by intentional introduction of nitrogen and aluminum into the growing crystal. Monocrystalline AlN was deposited using evaporated Al and ECR plasma derived N or NH3. Films <50 Å grown on the vicinal substrates had higher defect densities compared to those on the on-axis substrates due to the higher density of inversion boundaries forming at most SiC steps in the former material. Metal/AlN/6H-SiC(0001) thin film heterostructures which had a density of trapped charges as low as of 1 × 1011 cm−2 at room temperature were prepared without post growth treatment. Superior single crystal AlNSiC heterostructures were achieved when very thin AlN was deposited on the on-axis substrates. Single phase monocrystalline solid solutions of (AlN)x(SiC)1−x were deposited between 0.2 ≤ x ≤ 0.8. A transition from the zincblende to the wurtzite structure was observed at x ≈ 0.25.}, number={10}, journal={DIAMOND AND RELATED MATERIALS}, author={Kern, RS and Jarrendahl, K and Tanaka, S and Davis, RF}, year={1997}, month={Aug}, pages={1282–1288} }
 @article{davis_weeks_bremser_tanaka_kern_sitar_ailey_perry_wang_1997, title={Growth of AlN and GaN thin films via OMVPE and gas source MBE and their characterization}, volume={41}, ISSN={["1879-2405"]}, DOI={10.1016/S0038-1101(96)00152-9}, abstractNote={Thin films of AlN and GaN are deposited primarily via the common forms of organometallic vapor phase epitaxy (OMVPE) and molecular beam epitaxy (MBE). Sapphire is the most common substrate; however, a host of materials have been used with varying degrees of success. Both growth techniques have been employed by the authors to grow AlN and GaN primarily on 6H-SiC(0001). The mismatch in atomic layer stacking sequences along the growth direction produces inversion domain boundaries in the AlN at the SiC steps; this sequence problem may discourage the nucleation of GaN. Films of AlN and GaN grown by MBE at 650°C are textured; monocrystalline films are achieved at 1050°C by this technique and OMVPE. Donor and acceptor doping of GaN has been achieved via MBE without post growth annealing. Acceptor doping in CVD material requires annealing to displace the H from the Mg and eventually remove it from the material. High brightness light emitting diodes are commercially available; however, numerous concerns regarding metal and nitrogen sources, heteroepitaxial nucleation, the role of buffer layers, surface migration rates as a function of temperature, substantial defect densities and their effect on film and device properties, ohmic and rectifying contacts, wet and dry etching and suitable gate and field insulators must and are being addressed.}, number={2}, journal={SOLID-STATE ELECTRONICS}, author={Davis, RF and Weeks, TW and Bremser, MD and Tanaka, S and Kern, RS and Sitar, Z and Ailey, KS and Perry, WG and Wang, C}, year={1997}, month={Feb}, pages={129–134} }
 @article{kern_jarrendahl_tanaka_davis_1997, title={Homoepitaxial SiC growth by molecular beam epitaxy}, volume={202}, number={1}, journal={Physica Status Solidi. B, Basic Solid State Physics}, author={Kern, R. S. and Jarrendahl, K. and Tanaka, S. and Davis, R. F.}, year={1997}, pages={379–404} }
 @inproceedings{rossow_edwards_bremser_kern_liu_davis_aspnes_1997, title={In-plane optical anisotropies of Al(x)Ga(1-x)N films in their regions of transparency}, DOI={10.1557/proc-449-835}, abstractNote={ABSTRACT}, booktitle={III-V nitrides: symposium held December 2-6, 1996, Boston, Massachusetts, U.S.A.  (Materials Research Society symposia proceedings ; v. 449)}, publisher={Pittsburgh, Pa.: Materials Research Society}, author={Rossow, U. and Edwards, N. V. and Bremser, M. D.. and Kern, R. S. and Liu, H. and Davis, R. F. and Aspnes, D. E.}, year={1997}, pages={835–840} }
 @article{kern_davis_1997, title={Silicon carbide for high-temperature microelectronics: recent advances in material growth via gas source MBE and device research}, volume={46}, number={1-3}, journal={Materials Science & Engineering. B, Solid-state Materials for Advanced Technology}, author={Kern, R. S. and Davis, R. F.}, year={1997}, pages={240–247} }