Examination Committee

Prof Andrew W O POON, ECE/HKUST (Chairperson)
Prof Man Sun CHAN, ECE/HKUST (Thesis Supervisor)
Prof Zhi Yong FAN, ECE/HKUST

Abstract

The objective of the thesis is to study the current variation of the organic thin film transistor, to discuss current approaches towards aligning grains and to provide several morphological solutions instead of changing the fabrication process.

At first, we predicted that the effect of irregularities near the corner of an organic semiconducting layer can be suppressed by keeping extension on the either sides of the electrodes. We predicted that through the modeling of the fringe current.

Another major source of variation is the unpredictable grain orientation. Several organic transistor structures have been investigated by us and found to exhibit a reduced variation compared to the conventional transistors. Among the circular, waffle and planar structures; circular have the lowest theoretical variation. The waffle structure is area-efficient but the most area-efficient one is not corresponding to the lowest angle-dependent variation. Furthermore, the waffle and circular electrodes need a routing interconnect layer. The planar/ monolithic electrode structures can reduce grain-orientation dependent variation up to a certain level with a slightly lower area-efficiency compared to the waffle structure. Also, the monolithic structures have lower process variation and a higher yield. Circuit designers may choose the structure based on the required application and the available fabrication facility.