Papers by Keyword: p-Doping

Abstract: We have investigated the p-dopant potential of 14 different impurities (Be, B, F, Mg, Al,Ca, Sc, Cu, Zn, Ga, In, Ba, Pt, and Tl) within 4H-SiC via Density Functional Theory (DFT) calcu-lations using a hybrid density functional. We analyse the incorporation energies of impurity atomson Si and C sites as well as the character of lattice distortion induced by impurities. The calculatedthermal ionization energies confirm that Al and Ga on the Si site are the best candidates for p-dopingof 4H-SiC. Although we find some correlation of incorporation energies with atomic radii of impuri-ties, the difference in chemical interaction with neighbouring atoms and strong lattice distortions playimportant roles in determining the impurity incorporation energies and charge transition levels. Wefind Al to still be the best and most industrially viable p-dopant for 4H-SiC.

Abstract: We investigated defect composition in ZnO quantum structures – quantum wells and nanowires doped with Ag impurity. We investigated the influence of space and dielectric confinement on ionization energies of acceptor and compensation donor centers. These calculations show that in nanowire there is a optimal range of radius where the creation of ionized donors compensating hole conductivity, and consequently, improvement of hole conductivity, is possible to suppress.

Abstract: Quasi-thermodynamic model of SiC doping with Al in CVD from C₃H₈, SiH₄, and Al (CH₃)₃ on the Si-face is developed. The model is validated by quantitative agreement of calculated and experimental data on the Al concentration in SiC as a function of temperature, pressure, SiC growth rate, and TMAl flow rate. The model is shown to be consistent with the site competition mechanism of Al incorporation into SiC.

Abstract: An exhaustive experimental study of the influence of C/Si ratio on voluntary incorporation of nitrogen (N) and aluminum (Al) in 4H-SiC thin films is presented. The films were grown by chemical vapor deposition (CVD) in a horizontal, hot wall CVD reactor on Si- and C-face substrates, under Si-rich and C-rich conditions. Under some conditions the observed variation of dopant incorporation with C/Si ratio could be clearly attributed to the site competition effects, while in several cases other mechanisms have to be taken into account.

Abstract: In the present contribution, the trends in voluntary incorporation of aluminum in 4H-SiC homoepitaxial films are investigated. The films were grown on Si-and C-face 4H-SiC 8°off substrates by chemical vapor deposition (CVD) in a horizontal, hot wall CVD reactor. Secondary Ion Mass Spectrometry (SIMS) and capacitance-voltage (C-V) measurements were used to determine the Al incorporation in the samples. The influence of Trimethylaluminum (TMA) flow rate, growth temperature, growth pressure and C/Si ratio on the dopant incorporation was studied.

Abstract: Characterization of post implantation annealing steps is done by extracting the activation and compensation data of implanted Al atoms. Usually, this is done by Hall measurements. The preparation of Hall samples and temperature dependent Hall measurements, however, are rather complex compared to, e.g., temperature dependent resistivity measurements by 4-point probing. Therefore, a model for extracting relevant electrical parameters from resistivity data has been developed. The model is based on the neutrality equation and a temperature dependent mobility model.