The effect of high temperature annealing on Schottky diode characteristics of Au/ n-Si contacts

Abstract

The current–voltage and capacitance–voltage characteristics of Au/n-Si/Al Schottky barrier diode were measured in the temperature range of 100–800 °C. Au/n-Si/Al Schottky barrier diode annealed at temperatures from 100 °C to 400 °C for 5 min and from 500 °C to 800 °C for 7 min in N 2 atmosphere. The electronic parameters such as barrier height and ideality factor ( n) of the device were determined using Cheung's method. To determine whether or not a Schottky diode is ideal it can be used the ideality factor ( n) found from its forward current–voltage ( I– V) characteristics. It has been found that the value of Φ b (0.82 or 0.83 eV) remains constant up to 500 °C and 0.80 and 0.79 eV in 600, 750 °C respectively in the forward I– V mode. An ideality factor value of 1.04 was obtained for as-deposited sample. The ideality factor n varied from 1.04 to 2.30. The experimental results have shown that the ideality factor ( n) values increases with increasing annealing temperature up to 750 °C. This has been explained in terms of the presence of different metallic-like phases produced by chemical reactions between the Au and Si substrate because of the annealing process. The Φ b ( C– V) values obtained from the reverse-bias C −2– V curves of the as-deposited and annealed diode are in the range 0.99–1.12 eV. The difference between Φ b ( C– V) and the Φ b ( I– V) is in close agreement with values reported in literature. Besides Fermi energy level and carrier concentration determined by using thermionic emission (TE) mechanism show strong temperature dependence. It has been seen current–voltage characteristics of the diode show an ideal behavior.