Distribution of barrier heights in metal/n-InAlAs Schottky diodes from current–voltage–temperature measurements

The current–voltage characteristics of metal/n-InAlAs Schottky diodes were determined in the temperature range 90–300 K. Analysis of the measured characteristics allows the determination of the electrical parameters, the saturation current I0, the ideality factor n and the serial resistance Rs. The results show an increase of the Schottky barrier height φB0φB0 and a decrease of the ideality factor n   both with the increase of the temperature. The characteristics have been interpreted based on the thermionic emission (TE) mechanism with Gaussian distribution of the barrier heights of φ¯b0 is 0.96 eV and standard deviation σsoσso is equal to 0.128 V. In addition, the ln(I0/T2) vs. 1/T plot yields the effective Richardson constant of 4.65×10−3 A cm−2 K−2 for the metal/InAlAs diode which is lower than the known value of 10.1 A cm−2 K−2 for InAlAs. The modified Richardson plot shows a straight line relationship between ln(Is/T2)–(q2σ2so/2k2T2) vs. 1000/T, and gives a value of A*=9.2 A cm−2 K−2.