The Study Of Pentancene Organic Thin Film Transistors (OTFTs) Device

The material,the preparation method,and the thickness of insulator layers,will Play an important role in controlling the leakage current of the gate,as well as affecting the performances of the OTFTs devices.In this paper,we carried out our researches on OTFTs from the following three aspects:1.OTFTs insulator layers based on different materials.Firstly,we used RF reactive magnetron sputtering to fabricat the OTFTs devices with SiO₂ and Si₃N₄,the thickness of the insulator layers is 200nm,and the active layers of pentacene is 40nm.We found the device based on Si₃N₄ as insulator layers has got a small output current,but its insulation is much better.2.OTFTs insulator layers based on different preparation method.We used RF reactive magnetron sputtering and electron beam evaporation to fabricate the OTFTs devices based on SiO₂ as the insulator layers,the thickness is 200nm and the active layers of pentacene is 40nm.The insulator layers fabricated by electron beam evaporation has a much higher purity,and its insulation performance is much better than that of the insulator layers fabricated by RF reactive magnetron sputtering,which has many defects in crystal.3.OTFTs insulator layers based on different thickness.We used RF reactive magnetron sputtering and electron beam evaporation to fabricate the OTFTs devices based on SiO₂ as the insulator layers,the thickness is 150nm,200nm,250nm,the active layers of pentacene is 40nm.We found that no matter which preparation method we used,the leakage current is decreasing with the increase of the thickness,and thick insulator layer has got a better insulation performance.At last,we fabricated a new device base on ciruclar-channel.Then the output and the transfer characteristics of the devices,as well as a straight-channel device,was tested and analyzed.We found the straight-channel device has a lower threshold voltage and smaller channel resistance.But the output curves of the ciruclar-channel device is more steep,and the saturation current is greater than that of the straight-channel device, which means the ciruclar-channel device has better output and switch characteristics.