Investıgatıon Of Temperature Dependent Electrıcal Characterıstıcs Of The Au/C20h12/N -Si Schottky Barrıer Dıodes

Thesis Type: Postgraduate

Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey

Approval Date: 2015




In this study, Au/C20H12/n-Si Schottky barrier diodes (SBDs) were fabricated and their main electrical parameters such as reverse-saturation current (Io), ideality factor (n), zero- bias barrier height (Bo), series and shunt resistances (Rs, Rsh) were determined by using the forward bias current-voltage-temperature (I-V-T) characteristics as 1.974x10-7A, 6.434, 0.351 eV, 30.22  and 18.96 k at 160 K and 1.061x10-6A, 2.34, 0.836 eV, 5.82  and 24.52 k at 380 K, respectively. Experimental results show that the value of n decrease with increasing temperature, but ΦBo increases. The change in ΦBo with temperature is not agreement with negative temperature coefficient of forbidden bad-gap of semiconductor (Si). Thus, ΦBo vs n, ΦBo and (n-1-1) vs q/2kT plots were drawn to obtain an evidence of a Gaussian distribution (GD) of the BHs and all of them have a straight line. The mean value of BH ( ̅Bo) was found as 0.983 eV from the intercept of ΦBo vs n plot (for n=1). Also, the value of ̅Bo and standard deviation (s) were found as 1.123 eV and 0.151 V from the slope and intercept of ΦBo vs q/2kT plot. By using the modified Richardson plot, the ̅Bo and Richardson constant (A*) values were obtained as 1.116 eV and 113.44 from the slope and intercept of this plot, respectively. It is clear that this value of A* (=113.44 is very close to their theoretical value of 112 for n-Si. In addition, the energy density distribution profile of surface states (Nss) was obtained from the forward bias I-V data by taking into account the bias dependent of the effective barrier height (e) and ideality factor n(V) for four different temperatures (120, 200, 300, and 400 K). In conclusion, the I-V-T measurements of the Au/C20H12/n-Si SBD in the whole temperature range can be successfully explained on the basis of thermionic emission (TE) theory with GD of the BHs.