Temperature dependence of characteristic parameters of the Au/ C_(20)H_(12)-Si Schottky barrier diodes (SBDs) in the wide temperature range

摘要

Au/C_(20)H_(12)-Si SBD was fabricated and its characteristic parameters such as reverse-saturation current (I_0), ideality factor (n), zero-bias barrier height (Φ_(bo)), series and shunt resistances (R_s, R_(sh)) were found as 1.974 x 10~(-7) A, 6.434, 0.351 eV, 30.22 Ω and 18.96 kΩ at 160 K and 1.061 x 10"6 A, 2.34, 0.836 eV, 5.82 Ω and 24.52 kΩ at 380 K, respectively. While the value of n decreases with increasing temperature, Φ_(bo) increases. The change in Φ_(bo) with temperature is not agreement with negative temperature coefficient of forbidden band-gap of semiconductor (Si). Thus, Φ_(bo) versus n, Φ_(bo) and (n~(-1) - 1) versus 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 (Φ_(bo)) was found as 0.983 eV from the intercept of Φ_(bo) versus n plot (for n = 1). Also, the value of Φ_(bo) and standard deviation (σ_s) were found as 1.123 eV and 0.151 V from the slope and intercept of Φ_(bo) versus q/2kT plot. By using the modified Richardson plot, the Φ_(bo) and Richardson constant (A*) values were obtained as 1.116 eV and 113.44 A cm~(-2) K~(-2) from the slope and intercept of this plot, respectively. It is clear that this value of A* (=113.44 A cm~(-2) K~(-2)) is very close to their theoretical value of 112 A cm~(-2) K~(-2) for n-Si. In addition, the energy density distribution profile of surface states (D_(it)) was obtained from the forward bias I-V data by taking into account the bias dependent of the effective barrier height (Φ_l) and ideality factor n(V) for four different temperatures (160, 200, 300, and 380 K). In conclusion, the I-V-T measurements of the Au/C_(20)H_(12)-Si SBD in the whole temperature range can be successfully explained on the basis of thermionic emission (TE) theory with GD of the BHs.