The barrier height distribution in identically prepared Al/p-Si Schottky diodes with the native interfacial insulator layer (SiO2)

The Al/p-Si Schottky diodes (33 dots) with the native interfacial insulator layer (SiO2) were fabricated on the same quarter Si wafer. The Schottky barrier height (SBH), ideality factor (n), interface state densities (N-ss) and series resistance (R-s of these diodes have been calculated from their experimental for-ward bias current-voltage (I-P), reverse bias capacitance-voltage (C-V) and conductance-voltage (G/omega-V) measurements. Even though they are identically performed on the same quarter Si wafer, the calculated values of SBH have ranged from 0.680 to 0.736eV, and ideality factor n from 1.62 to 2.87, and interface state densities N-ss from 0.395 x 10(13) to 1.2 x 10(13) eV(-1) cm(-2) and series resistance Rs from 623 to 4900 Omega. It was found that the values of barrier height Phi(B) obtained from C-V characteristics is larger than that of the value from I-V characteristics. The energy distribution of surface state density profiles for the selected six samples Al/p-Si Schottky diodes was determined from forward bias I-V characteristics by taking the bias dependence of the effective barrier height into account at room temperature. The experimental values of SBHs distributions obtained from the I-V and C-2 -V characteristics have been fitted by a Gaussian function, and their mean values of SBHs have been calculated to be 0.708 and 0.810eV, respectively. Experimental results show that the interface states at a native insulator layer between metal and semiconductor play an important role in the value of the SBH, ideality factor, series resistance and the other main electrical parameters of Schottky diodes. (c) 2007 Elsevier B.V. All rights reserved.