| Co-Investigator(Kenkyū-buntansha) |
PENSL G Univ.Erlangen, Inst.Appl.Phys.Senior Res., 応用物理研究所, 主幹研究員
CHOYKE W.J Univ.Pittsburgh, Dept.Physics, Prof., 物理学科, 教授
|
|---|
| Research Abstract |
Silicon carbide (SiC) is a IV-IV compound semiconductor material with a wide bandgap. The wide bandgaps of SiC give the material very high breakdown field, about ten times higher than that of Si or GaAs. The energies of optical phonons in SiC are as high as 100-120meV,which leads tohigh saturated electron drift velocity (2x10^7 cm/s in 6H-SiC) and high thermal conductivity (4.9W/Kcm). These outstanding properties and controllable p- and n-type doping during crystal growth make SiC a very attractive semiconductor material. Chemical vapor deposition (CVD) of silicon carbide (SiC) on SiC {0001} substrates and device applications have been investigated. Polytype-controlled epitaxial growth of SiC,which utilizes step-flow growth on off-oriented SiC {0001} substrates(step-controlled epitaxy), isproposed, and the detailedgrowth mechanism is discussed. In step-controlled epitaxy, SiC growth is controlled by the diffusion of reactants in a stagnant layr. Critical growth conditions where the growth mode changes from step-flow to two-dimensional nucleation are predicted as a function of growth conditions using a model describing SiC growth on vicinal {0001} substrates. Step bunching on the surfaces of SiC epilayrs, nucleation, and step-dynamics are also investigated. High quality of SiC epilayrs was elucidated through low-temperature photoluminescence, Hall effect, and deep level measurements. Excellent doping controllability in the wide range has been obtained by in-situ doping of a nitrogen donor and aluminum/boron acceptors. Recent progress in SiC device fabrication using step-controlledepitaxial layrs is studied. Intrinsic potential of SiC has been demonstrated in the excellent performance of high-power, high-frequency, and high-temperature SiC devices, which will exploit novel electronics.
|
