AVS 52nd International Symposium
    Electronic Materials and Processing Tuesday Sessions
       Session EM-TuP

Paper EM-TuP26
Electron Spin Resonance Investigation of the Crystallization of Silicon Carbide Thin Films

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Electronic Materials and Processing Poster Session
Presenter: M. Tabbal, American University of Beirut, Lebanon
Authors: M. Tabbal, American University of Beirut, Lebanon
E. Hannoun, American University of Beirut, Lebanon
T. Christidis, American University of Beirut, Lebanon
S. Isber, American University of Beirut, Lebanon
Correspondent: Click to Email
Crystalline silicon carbide (SiC) is the material of choice to manufacture electronic devices that can function under extreme conditions such as high temperature, high power, high frequency and high radiation environments. This work consists of an electron spin resonance (ESR) study of paramagnetic defects in crystallized SiC thin films. The films were synthesized on silicon (Si) substrates by ablating a pure SiC target in vacuum using a pulsed KrF excimer laser. Crystallization of the films was performed by deposition at temperatures exceeding 1000 K and by subsequent high temperature annealing. ESR measurements were performed at various temperatures at X-Band and Q-Band frequencies. It is found that deposition at temperatures between 1000 and 1200 K lead to polycrystalline films with an ESR signal having a g-value of 2.0028, that is attributed to carbon defects. Increasing the deposition temperature lead to a decrease in the spin density as well as broadening of the ESR signal, with typical line-widths ranging between 5.5 and 8 G. In addition, the ESR line was found to be temperature dependent with lines narrowing down to 4.8 G for measurements performed at 77 K. Such broadening phenomena could be explained by an enhanced connectivity of the paramagnetic defects that could lead to conducting channels in the layers. Post-deposition annealing of the films, in vacuum, to 1400 K leads to a considerable decrease in spin density as well as to significant narrowing of the ESR signal down to 3.2 G. Furthermore, annealing was found to eliminate the temperature dependent contribution to the ESR line-width. These effects were found to occur along with an enhancement of the crystalline quality of the films, as deduced by XRD. A phenomenological model describing the effect of deposition temperature and subsequent annealing on the paramagnetic defects in polycrystalline SiC films will be presented.