以噴墨系統製作有機電子被動元件與有機薄膜電晶體

Abstract

自從1980年代中期，功能性有機半導體元件開始嶄露頭角之後，這方面的技術就不斷的在進步，成果日新月異。近年來，有機半導體技術在微電子領域相關的研究成果亦不斷精進。到了最近，有機導體、半導體的功能性墨料被開發出來。由於這些功能性墨料的現，讓原本與電子產業不相關的低成本印刷技術有了參與的機會。噴墨製程擁有大量生產、製程速度快、步驟簡單以及價格低廉等重要的特點，對於有機電子產業來說是非常適合的製程方式。噴墨印刷便是低成本製程方式之一，它不但有上述的優點，還擁有即時與局部修改圖案的特長。 本論文成功地展示了將噴墨製程系統應用於製作有機電子件—電阻、電容、電晶體—的適用性及能力。噴印電阻的部分，除了噴出PEDOT/PSS導電高分子水溶液，製作成電阻元件外，並且為了改善導電率，在PEDOT/PSS導電高分子水溶液中摻雜DMSO，也成功的噴印出電阻元件，並且達到比原廠所宣稱的導電率(200 S/cm)更高的結果---333 S/cm。 在噴印電容方面，首先以異丙醇與DMSO經適當比例混合，作為介電絕緣層材料PVP的溶劑，降低了所謂咖啡環現象，成膜性得到了大幅的改善。接著也順利噴出電容，並且達到了目前被製作出的全有機電容中，單位面積最高的電容值---67PF/1.2mm^2 。 噴印電晶體方面，單純利用噴墨系統成功製作出120um通道長度。並利用滴鑄 P3HT 半導體材料 ， 製作出P3HT 有機薄膜電晶體 ，載子遷移率達到了0.00545cm^2/V-s。另一方面配合真空熱蒸鍍Pentacene製作有機薄膜電晶體最終達到0.02cm^2/V-s 以上的載子遷移率。 本論文中所完成之有機噴墨電子機台亦可成功製作所有電路基本元件，對下一步之噴墨的有機電路製作奠下良好的基礎。

During 1980’s, functional organic devices were proposed. After that, the technology has been advanved dramatically. This trend continuous for the past few years as more and more researchers has begun to apply organic semiconductor technology to microelectronics and target on the application of e-paper, flexible display, and plastic chips. With these solution based organic functional materials become widely available, low cost printing industry has found its way to impact microelectronics field. There are many advantages of printing based process, which includes quick time to mass production, high manufacturing speed, easy to operate, and low cost, etc. As inkjet printing is one of the printing manufacture methods, it has all of the above-mentioned merits. Nevertheless, inkjet printing provides us with a tool to modify the desired pattern globally or locally. In this dissertation, the potential of using inkjet printing system to manufacture organic electronic devices such as resistors, capacitors, and transistors, etc. were shown. As using resistors by inkjet printing, it was shown that PEDOT/PSS water solution can be adopted by the inkjet printing system. On the other hand, in order to improve conductivity, DMSO was added into the PEDOT/PSS water solution. The resistors were also successful manufactured by inkjet printing system using PEDOT/PSS solution with DMSO as addtitive. Its conductivity is 333 S/cm much higher than previous published result, 200 S/cm. Making capacitors by inkjet printing were also achieved by using PVP as the dielectric layer. Proper solvent ratio for mixing isopropanol and DMSO was identified, which eliminates the “coffee ring” effect and can improve morphology of the PVP thin film. The capacitor was successfully fabrciated, and very high capacitance value per unit area of organic capacitors, 67PF/1.2mm^2 was achieved. In the process of making transistor by inkjet printing, an all prnting organic field effect transistor with 120um channel length was successfully made. The active layer is fabrciated by drop casting P3HT and the mobility obtained is 0.00545cm^2/V-s . Pentacene was also tried to deposite with thermal evaporator as active material and the mobility of the Pentacene transistor obtained was found to be higher than 0.02cm^2/V-s. The passive and active organic electronic components are successfully demonstrated to be able to fabricate using all inkjet printing method in this dissertation, and provide a good starting point on the fabrication of all organic all printed electronic circuits.