Rectified Schottky diodes that use low-cost carbon paste/InGaZnO junctions

IGZO-based Schottky diodes have applications in high-speed electronics. However, these devices generally require noble metals to form a Schottky contact, which was one of the problems for their early commercialization. This study demonstrates the successful use of a semi-transparent carbon paste (CP) that is low-cost and which has a high work function as the Schottky contact for a Schottky junction for a-IGZO. The effect of the sintering temperature for CP on the resistivity, bulk crystallization, number of defects and work function ($\Phi$) are respectively determined by four-point resistivity measurement, X-ray diffraction, Raman spectroscopy, and surface Kelvin probe microscopy. The electrical properties of the Schottky diodes are also determined using current-voltage measurements and capacitance-voltage characteristics. After sintering, the crystalline quality of CP is improved so the series resistance of IGZO-based Schottky diodes decreases. Increasing the sintering temperature of the CP produces an increase in the work function of 0.18 eV, which gives a higher Schottky barrier height and better rectified performance. Using CP as the Schottky contact allows the manufacture of low-cost high performance IGZO-based Schottky diodes. It is hence expected that our scheme will be of great importance for the IGZO-based Schottky diode in the industrial application integrated with transistors.