Seminar

Date 2015-09-15 

The Fall Semester Seminar

 

■ Topic : Application and Device Characterization Methods of Oxide Semiconductor Thin Film Transistor

                    
■ Speaker : Prof. Sanghun Jeon (Dept. of Applied Physics, Korea Univ.)
 
■ Date & Time : September 15 (Tue), 16:00
 
■ Venue :  KAIST Applied Engineering B/D(W1), Multimedia Lecture Hall (1st Floor)
 
■ Abstract : Ever evolving advances in oxide semiconductor materials and devices continue to fuel leading edge developments in display/sensor technology, transparent electronics, semiconductor memory device, image sensor, and power device thanks to new integration processes, enabling large area processing on rigid and flexible substrates. Oxide semiconductor offer a host of advantages such as low cost and high scalability, in addition to seamless heterogeneous integration with a host of other inorganic and organic materials in view of its low thermal budget in processing which provides integration flexibility. This has spawned a wealth of applications. In the first part of the presentation, various application of oxide semiconductor thin film devices will be presented.

Oxide semiconductor which is of our interest is formed of amorphous or nano-crystalline phase at low temperature, inherently having a certain amount of defects. Thus actual understanding of the impact of defects at the interface as well as the bulk on oxide thin film transistor (TFT) characteristics is the crucial work for the successful development of device. To this end, we employed various device characterization techniques such as pulse I-V measurement, transient current and frequency dependent discharging current analysis methods. So far, conventional DC I-V measurement method was used to evaluate basic device characteristics. However, due to charge trapping effect, this method leads to the underestimation of actual device performance. In order to extract the intrinsic mobility value and evaluate the impact of fast transient charge trapping on the mobility of oxide TFT, we introduced ultra-fast pulsed current-voltage (I-V) method allowing to determine the intrinsic device performance in charge trap-free environment. Also the modelling on transient characteristics provides understanding on the dynamic nature of charge trapping in oxide TFT. In addition, fast discharging current analysis was adopted to acquire trap profile of interface of semiconductor/insulator. These results present that pulse, transient and discharging current analysis techniques will be a very important technique for evaluating the performance of oxide thin film devices.