Sputtering Growth of p-Type CuXO Semiconductors and Their Applications on Electronic Devices
Date Issued
2014
Date
2014
Author(s)
Chen, Wei-Chung
Abstract
Oxide–semiconductor–based thin films transistors (TFTs), due to their various merits, have attracted much attention and been regarded as a promising next-generation TFT technology for flexible electronics and displays in recent years. In spite of rapid progresses of n-type oxide TFTs, only few p-type oxide-based transistors had been reported so far and their properties and fabrication techniques are still not good enough for practical applications. However, to realize low-power and high-performance complementary TFT circuits or to make the active matrix organic light-emitting diode displays compatible with conventional OLED structures, p-type oxide semiconductors are highly desired. Among all p-type oxides reported, copper oxide (CuXO) is considered one of the most promising candidates for realizing practical p-channel devices. However, the properties of CuXO-based TFTs are not yet good enough for practical applications, necessitating further studies. In this dissertation, we firstly investigated sputtering deposition of p-type CuXO using the Cu2O target in Ar atmosphere. The effects of the sputtering power, working pressure and annealing processes on compositions, structures, chemical bonding and electrical properties of deposited CuXO films were studied. Results show that polycrystalline and p-type CuO-dominant or Cu2O-dominant films could be readily obtained by carefully controlling the sputtering power, working pressure under post-annealing treatment. p-type CuO TFTs using CuO-dominant films were also demonstrated. Next, we report successful implementation of room-temperature-processed flexible n-InGaZnO/p-Cu2O heterojunction diodes on polyethylene naphthalate (PEN) plastic substrates using the sputtering technique. Using n-type InGaZnO and p-type Cu2O films deposited by sputtering at room temperature, flexible n-InGaZnO/p-Cu2O heterojunction diodes were successfully fabricated on PEN plastic substrates. The characterization of the frequency response of the room-temperature-processed flexible n-InGaZnO/p-Cu2O heterojunction diode rectifiers indicated that they are sufficient for high-frequency (13.56 MHz) applications. Preliminary bending tests on diode characteristics and rectifier frequency responses indicate their promise for applications in flexible electronics.
Subjects
RF sputtering
p-type oxide semiconductors
thin film transistors
flexible diode rectifiers
RFID
Type
thesis