Soon Sung Yoo

Abnormal Output Characteristics of p-Type Low Temperature Polycrystalline Silicon Thin Film Transistor Fabricated on Polyimide Substrate

We report on an abnormal output characteristics in p-type low temperature polycrystalline silicon thin-film transistors fabricated on polyimide (PI); negative differential conductance behavior is often observed in saturation region of drain current from large width devices. To understand such abnormal output characteristics, device dimension dependence was studied in a systematic way. As a result, we found that enhanced self-heating is mainly responsible originating from the poor thermal conductivity of PI substrate. A related degradation model is also proposed.

Electromechanical properties of amorphous indium–gallium–zinc-oxide transistors structured with an island configuration on plastic

A comparative study of the electromechanical properties was carried out on a low-temperature-processed amorphous indium–gallium–zinc-oxide thin-film transistor, particularly with regard to the structural design of the device under the stress accumulation of an outward bending surface. Shown herein is the reliable electromechanical integrity of island-structured devices against the mechanical strain at bending radii of mm order. The onset of crack strain also closely corresponded to the electrical failure of the stressed device. These results revealed that the island configuration on the bending surface effectively suppresses the stress accumulation on sheets composed of inorganic stacked layers in a uniaxial direction.

Highly bendable characteristics of amorphous indium–gallium–zinc-oxide transistors embedded in a neutral plane

The electromechanical response of an amorphous indium–gallium–zinc-oxide (a-IGZO) thin-film transistor (TFT) fabricated on a polyimide substrate was investigated as a function of the neutral axis location and strain history of the bending system. Here, we demonstrate the pronounced bending characteristics of a-IGZO TFTs and their backplane under extreme mechanical strain when they are embedded in a neutral plane (NP). After being subjected to tensile stress, the devices positioned near the NP were observed to function well against a cyclic bending stress of 2 mm radius with 100,000 times, while TFTs farther from the neutral surface exhibited modified electrical properties.