Design And Fabrication Of High Performance Organic Thin-film Transistors And Its Cell Curcuit

Organic semiconductors have been the focus of considerable research for their potential applications in large area, low cost, ease of processing and/or flexible electronics. They are widely used for electronic and optoelectronic devices including light-emitting diodes, thin film transistors, solar cells and memories.For large-area, flexible display, the driving trasistors should have high compatibility with flexible substrate. Besides high performance, easy processing of the devices is a prerequisite for commercialization of organic electron. However, in most cases, the devices were fabricated with organic semiconductors as active component on an expensive Si wafer. Otherwise, on the study of organic integrate circuit design and simulation, there was not a communal OTFT's model using in Spice simulation at the present time, so it was difficult to design and simulate the complicated organic integrate circuit.In this thesis, we fabricated top gate structure copper phthalocyanine (CuPc) OTFTs with fluorides as the gate dielectrics. In addition to low cost and ease of integration, the same method used for the formation of organic semiconductor and fluoride gate dielectric films greatly simplifies the fabrication process of devices and avoids the contamination of impurity. On these bases, we studied their model, integration and application in organic display driving.(1) Calcium fluoride (CaF₂) was used as gate dielectrics to fabricate organic CuPc thin film transistors on glass sustrates by thermal evaporation. By adding Nylon as modificatory layer between dielectric layer and active layer, improving evaporation speed of CuPc, we successfully reduced the leakage current and increased the injection current. The devices showed a good electrical characteristic which the threshold voltage was -4.2V and the carrier field effect mobility was 0.67cm²/V.s, The gate leakage current was reduced from 10-6 A to 10-8 A by two orders. (2) On the study of organic integrate circuit design and simulation, there was not a communal OTFT's model using in Spice simulation at the present time, so the OTFT's model was explored. Based measure and analysis the electrical characteristic of the CuPc-OTFTs fabricated by thermal evaporation, the parameters using in Spice simulation were extracted, and imitating high precise Level 62 RPI TFT's model, the CuPc-OTFT model using in H-Spice(VER: U-2003.09) was established. Finally comparing the device's electrical characteristic curve of simulation with measure result, it was known the proposed model was fitting well with the device we fabricated.(3) Using the proposed model, several common digital circuits(inverter, NAND gate and current mirror) were simulated, their layouts were designed. At the same time, those circuits were fabricated, the logic functions of those circuits were measured. We analysed the main factor of influencing OTFT's performance. It lay a foundation for optimizing organic integrate circuit design and simulation.(4) Based on the most OLED using transparent ITO acting as anode, the OTFT-OLED and OTFT-AMOLED organic optoelectronic integrated pixels were designed, which driven by OTFT with double-insulator layer and top-gate structure,fabricated by fully-evaporation method on the ITO coated glass substrates. also we desiged their layouts,and simulated their function. Compared with other same devices, the preparation technology was simplified obviously. And, the source-drain electrode of OTFT and the anode of OLED can be prepared by photolithography technique, which is propitious to improving the operation current and the display brightness.