Improvement of Characteristics in Highly Reliable thin Film Diode with Anodic Tantalum Pentoxide by Low Temperature Anne
- PDF / 316,219 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 26 Downloads / 189 Views
IMPROVEMENT OF CHARACTERISTICS IN HIGHLY RELIABLE THIN FILM DIODE WITH ANODIC TANTALUM PENTOXIDE BY LOW TEMPERATURE ANNEALING CONDITIONS Chan-Jae Lee, Sung-Jei Hong, Sung-Kyu Park, Yong-Hoon Kim, Min-Gi Kwak, Won-Keun Kim and Jeong-In Han Information Display Research Center, Korea Electronics Technology Institute, 455-6 PyungTack, KyungGi, Korea; ABSTRACT In this study, the quality of thin film diode (TFD) as a switching device for active-matrix liquid-crystal-displays (AM-LCDs) was enhanced by low temperature annealing conditions with high reliability and good electrical properties. Device was composed with Ta as bottom electrode, anodic Ta2O5 as insulator layer and top electrode. Two types of material such as Ti and Cr were evaluated as a top electrode of the TFD device to optimize the symmetry of current-voltage characteristic curve, respectively. The annealing was done at low temperature conditions below 350oC. The low temperature annealing improved the TFD device with nearly perfect symmetry under high electric field. INTRODUCTION Metal-insulator-metal (MIM) type thin-film-diode (TFD) device is widely used in many applications in flat panel displays and integrated circuit fields, etc. In recent, the TFD device on plastic film substrate increasingly arises as a switching device of active matrix liquid crystal display (AM-LCD) for mobile communication where the low power consumption and the low weight are required [1]. The switching device demands good current-voltage (I-V) characteristics such as low threshold voltage and symmetry. The characteristics are determined by electrode, annealing condition, etc. For achieving the good properties, annealing process was done under the high temperature conditions ranging from 500oC to 800oC [2], but these conventional conditions cannot be applied to fabricate the device since the temperature is higher than that of glass transition of the plastic film. Therefore, in order to overcome the bottleneck, I-V characteristics under the lower temperature annealing conditions should be optimized. In this study, we investigated the effect of low temperature annealing conditions on the characteristics of the TFD device. The annealing treatment was performed at low temperature region below 350oC. The characteristics according to top electrode materials, Cr and Ti were R6.6.1
compared respectively. Interfacial reaction between the insulator and the electrode was observed by high resolution (HR) TEM, and the effect on the I-V characteristics was evaluated and optimized. EXPERIMENTAL DETAILS As a substrate for TFD device, glass and Si were used respectively. The TFD device on Si substrate was fabricated to analyze the interfacial reaction with RBS and AES. Firstly etch-stop layer was formed on the substrate in order to prevent the damage by Ta etching solution consisting of HF, HNO3, and H2O. The bottom electrode was formed using 200nm thick Ta on the substrate by sputtering and photolithography. In case of glass, selected area of the Ta electrode pattern was anodized to form an insula
Data Loading...
