Fabrication Of N-channel IGZO TFT And P-channel Organic TFT And Their Application In Hybrid CMOS Inverter

Thin film transistor (TFT) is the key component of the display panel, suchas active-matrix liquid crystal display (LCD) and active-matrix oganic light emittingdiodes (AM-OLED)，It is mainly used for making the driving circuit of display panel.In recent years, compared to the traditional silicon (amorphous silicon, polycrystallinesilicon) TFT devices, scientists from all over the world and display industry pay moreattention to two kinds of new type TFTs, they are InGaZnO TFT and organic TFT(OTFT), respectively. InGaZnO (IGZO) is a kind of wide band gap amorphous oxidebased on the structure of ZnO semiconductor. Compared with Si TFTs, TFTs withIGZO as channel have many advantages, such as high transmittance, high field effectmobility and low preparation temperature. TFT devices using organic semiconductoras the channel is OTFT, with the advantages: low preparation temperature, simplifiedtechnological process, suitable for large area and widely material sources.However, there are still some bottlenecks in the the process of practicalapplication of large size display panel with IGZO TFT and OTFT. IGZO is n-typesemiconductor material, but p-type conductive ZnO is very difficult to obtain,therefore, using IGZO TFT can only obtain n-type practical devices. On the otherhand, Organic semiconductor materials are mostly p-type semiconductor, the electronmobility of n-type organic semiconductor is very low, Therefore, using organicsemiconductor materials can only obtain p-type practical devices. However, large sizedisplay driver circuit need complementary TFT integration device (CMOS), becausethe complementary TFT driving circuit can greatly reduce the power consumptioncompared with single channel TFT circuit polarity. It is obviously that single IGZOTFT and OTFT can not meet the requirements of large size display panel drivercircuit.According to the above problem, this paper designed a hybrid CMOS invertermade of IGZO TFT and P3HT TFT. Device is composed of independent n IGZO TFTand p P3HT TFT, which is typical unipolarity CMOS devices. IGZO and P3HTchannel layer preparation adopted solution method under low temperature process,possess good technology compatibility. Thus, our inverter obtanied high performance,when the drian voltage is30V, the voltage gain was~14, the mobility of IGZO TFTand P3HT TFT were0.27and0.0038cm2/V·s. We studied the influence of differentannealing temperature on IGZO film growth before the preparation of the devices, finally chose the IGZO film with annealing temperature at450oC to TFT devices. Inaddition, this paper also studied the pentacene growth on different insulation layerwith different surface roughness. It is concluded that PMMA with roughness of0.25nm is the best insulation layer. Then, we discussed the influence of deposition rate onthe growth of pentacene film. The crystallinity of pentacene is best when depositionrate is0.05nm/s and the roughness is0.75μm.