Study Of The Performance Of Amorphous In-Ga-Zn-O-Based Schottkv Diode

In contrast with pn junction, the current transport of Schottky diode is due to majority carriers. The advantages of high response rate and low positive bias made Schottky diodes widely used in direct current and microwave fields. In this paper, amorphous oxide semiconductor (AOS) is introduced due to their superior electrical properties, such as high carrier mobility (>10 cm2/Vs), optical transparency, large-area uniformity and low-processing temperature. These properties make it possible in use of flexible electronics. Here we studied the performances of In-Ga-Zn-O Schottky diode.This paper includes three parts:(1) Simply introduced the principle of Schottky diode, including the formation of barrier, current transport, junction capacitance and breakdown voltage. Listed the equations of Ⅰ-Ⅴ and C-V characteristics. Based on these equations, different parameters are derived.(2) The experiment processes and equipment in fabricating IGZO schottky diodes are also introduced.(3) The results of experiments are introduced.Although thin-film transistors based on indium gallium zinc oxide (IGZO) have been intensively studied, very limited research has been reported to date on IGZO-based diodes even though diodes serve as a key component in most circuits and microwave front-end rectifier. In this work, Schottky diodes was fabricated and optimized under a range of IGZO deposition conditions, such as different anode metals, different RF powers, different oxygen content and different IGZO thicknesses. Our experiments reveal a dependence of the breakdown voltage of IGZO Schottky diodes on different fabrication conditions. However, either higher RF power or higher oxygen partial pressure leads to degraded quality of the contact interface and bulk IGZO film. By using relatively low sputtering power (≤70 W) and appropriate oxygen content of sputtering atmosphere (～2.5-5%), high-performance diodes have been achieved with rectification ratio, ideality factor, barrier height, and breakdown voltage of 1.25×105,1.14,0.73 eV, respectively. The devices with a Pd anode and a 200-nm-IGZO layer have breakdown voltage up to-15 V. All the processes were carried out at room temperature without any thermal treatment showing the possibility of achieving high performance Schottky diodes on flexible plastic substrate.