In:
ECS Meeting Abstracts, The Electrochemical Society, Vol. MA2016-02, No. 33 ( 2016-09-01), p. 2164-2164
Abstract:
Low temperature poly-Silicon (LTPS) thin film transistor (TFT) and Oxide TFT are developed for the better performance of the active matrix display. Recently, oxide TFT has been investigated intensively due to simple process and higher mobility than amorphous silicon TFT. Typical parameters of TFT are mobility, threshold voltage and On/Off ratio which are influenced by gate insulator. The widely used material for gate insulator is SiO 2 which is rich in the earth and inexpensive. But vacuum equipments like the plasma enhanced chemical vapor deposition (PECVD) and the RF Magnetron sputter need large investment and maintenance cost than non-vacuum process. Oxide TFT of top gate structure reduces the parasitic capacitance between source-drain and gate metal. The plasma damage during deposition of gate insulator on an oxide active layer cause the defects which deteriorate TFT characteristics. However, the gate insulator by solution process reduces the defects by plasma process. SU-8 which is a negative photoresist (PR) has been being used widely in micro electro mechanical system (MEMS). It is constituted with octuple epoxy groups and includes photosensitize to react with UV light. The polymer network generated by cross-linking has mechanical and chemical stabilities and high electrical resistance. In this experiments, SU-8 was used for the gate insulator of the oxide TFT and investigated the effect of the SU-8 gate insulator on the oxide TFT. In this paper, we investigated the characteristics of gate insulator of SU-8 as changing UV exposure time to SU-8. SU-8 was coated by spin coating with 2000 rpm on a p-type Si wafer. After soft-bake for 1.5 min at 95˚C, UV of 365 nm was exposed at an energy of 320mJ/s. Exposure times were varied as 30s, 60s, 120s, and 240s. After UV exposure, hard bake was done for 20 min at 115˚C. An Al layer was deposited on SU-8, and electrical properties of the SU-8 were measured after post-annealing. Figure 1 shows the current densities of the SU-8 insulators for various exposure time from 30s to 240s. As shown in Fig. 1, the leakage currents decreased as the exposure time increased from 30s to 240s. For the gate insulator of the oxide TFT, the proper UV exposure is important. Figure 1
Type of Medium:
Online Resource
ISSN:
2151-2043
DOI:
10.1149/MA2016-02/33/2164
Language:
Unknown
Publisher:
The Electrochemical Society
Publication Date:
2016
detail.hit.zdb_id:
2438749-6
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