Effect of annealing on the electronic parameters of Au/poly(ethylmethacrylate)/n-InP Schottky diode with organic interlayer

A thin poly(ethylmethacrylate) (PEMA) layer is deposited on n-InP as an interlayer for electronic modification of Au/n-InP Schottky structure. The electrical properties of Au/PEMA/n-InP Schottky diode have been investigated by current–voltage (I–V) and capacitance–voltage (C–V) measurements at different annealing temperatures. Experimental results show that Au/PEMA/n-InP structure exhibit a good rectifying behavior. An effective barrier height as high as 0.83 eV (I–V) and 1.09 eV (C–V) is achieved for the Au/PEMA/n-InP Schottky structure after annealing at 150 °C compared to the as-deposited and annealed at 100 and 200 °C. Modified Nordeʹs functions and Cheung method are also employed to calculate the barrier height, series resistance and ideality factors. Results show that the barrier height increases upon annealing at 150 °C and then slightly decreases after annealing at 200 °C. The PEMA layer increases the effective barrier height of the structure as this layer creates a physical barrier between the Au metal and the n-InP. Termanʹs method is used to determine the interface state density and it is found to be 5.141 × 1012 and 4.660 × 1012 cm−2 eV−1 for the as-deposited and 200 °C annealed Au/PEMA/n-InP Schottky diodes. Finally, it is observed that the Schottky diode parameters change with increasing annealing temperature.