学術雑誌論文 Double negatively charged carbon vacancy at the h- and k- sites in 4H-SiC: Combined Laplace-DLTS and DFT study

Capan, Ivana  ,  Brodar, Tomislav  ,  Pastuovic, Zeljko  ,  Siegele, Rainer  ,  Ohshima, Takeshi  ,  Sato, Shinichiro  ,  Makino, Takahiro  ,  Snoj, Luka  ,  Vladimir, Radulović  ,  José, Coutinho  ,  J. B. Torres, Vitor  ,  Demmouche, Kamel

123 ( 161597 )  , pp.1 - 6 , 2018-02 , American Institute of Physics
内容記述
We present results from combined Laplace-Deep Level Transient Spectroscopy (Laplace-DLTS) and density functional theory studies of the carbon vacancy (VC) in n-type 4H-SiC. Using Laplace-DLTS, we were able to distinguish two previously unresolved sub-lattice-inequivalent emissions, causing the broad Z1/2 peak at 290K that is commonly observed by conventional DLTS in n-type4H-SiC. This peak has two components with activation energies for electron emission of 0.58 eV and 0.65 eV. We compared these results with the acceptor levels of VC obtained by means of hybrid density functional supercell calculations. The calculations support the assignment of the Z1/2 signalto a superposition of emission peaks from double negatively charged VC defects. Taking into account the measured and calculated energy levels, the calculated relative stability of VC in hexagonal (h) and cubic (k) lattice sites, as well as the observed relative amplitude of the Laplace-DLTS peaks, we assign Z1 and Z2 to VC(h) and VC(k), respectively. We also present the preliminaryresults of DLTS and Laplace-DLTS measurements on deep level defects (ET1 and ET2) introduced by fast neutron irradiation and He ion implantation in 4H-SiC. The origin of ET1 and ET2 is still unclear.

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