Electrical properties of nickel-low-doped n-type gallium arsenide Schottky-barrier diodes

The forward current characteristics of nickel-low-doped n-type gallium arsenide Schottky-barrier diodes are measured over the temperature range 90.5-434 K. The ideality factor and its temperature dependence is determined and found to decrease with increasing temperature according to the relationship n(T) = 11.4T^{-1/2} +0.444 to within ±4 percent. This is in agreement with the theoretical analysis of Strikha, who predicted a temperature dependence law between T-1and T^{-1/2} . The barrier height is determined from both the saturation current and the capacitance methods. A modification is made to the forward current expression, which results in good agreement between the values of the barrier height obtained from both methods over a wide temperature range. The barrier height is found to decrease with increasing temperature at a rate of 5.8 × 10 -4 V/K. Comparison with the dependence of the energy gap on temperature in GaAs suggests that the observed change in the barrier height is equal to that of E g .