Semiconductor Devices Based On A-IGZO Thin Film Materials

In recent years, the Thin Film Transistor (TFT) has become a hot research topic, and has been widely used, it is expected to become the next generation of driver components of the displays; since self-switching diode is proposed, because of its simple fabrication process and the characteristics of planar device, has been widely researched.The investigation in this paper consists of two parts, one is making high performance amorphous indium gallium zinc oxide thin film transistors with poly (methyl meth acrylate) as insulator, another is making amorphous indium gallium zinc oxide self-switching diodes(SSD).(1)High performance amorphous indium gallium zinc oxide thin film transistors with poly (methyl meth acrylate) as insulatorFirstly,we make high performance a-IGZO TFT with SiO2 as insulator,we find the best conditions,for example the sputtering power, sputtering gas, film thickness, annealing conditions and the materials of source and drain.Then we make High performance amorphous indium gallium zinc oxide thin film transistors with poly (methyl meth acrylate) as insulator based on the above conditions. We study the effect of annealing temperature of PMMA on the performance of the device.The annealing temperature is 120℃,130℃,140℃,150℃,respectively. We found that if the annealing temperature is too low, the leakage current of the device is larger, the yield is low, under the condition of 150℃, the device is stable, leakage current is minimum, the yield is high;We study the treatment on the interface of the IGZO,for example,150℃,20min with hot plate;UV ozone 20min;UV ozone 20min and then 150℃,20min with hot plate,and no treatment,we found that there is no obvious effect on the device with the different treatments.We study the treatment on the PMMA,for example,UV ozone 20min,UV ozone 20min and then 150℃,20min with hot plate,UV exposure 20min and no treatment,we found that the device without treatment is good. Lastly,we study the material of gate,for example Ti、Al,we found the Al with thermal evaporator is better.(2)Make amorphous indium gallium zinc oxide SSD (self-switching diode)We prepare 30nm amorphous IGZO film with sputter,then we make SSD on it,we study the effect of wet etching and dry etching on morphology of SSD,about wet etching,we use dilute hydrochloric acid and dilute acetic acid etching the a-IGZO respectively;about dry etching,we use CH4 and H2 as etching gas;lastly we use Ti and Ti/Au as electrodes.