PVD工艺对IGZO薄膜结晶化的影响

Effect of PVD Process on the Crystallization of IGZO Thin Films

在G4.5实验线上,采用射频磁控溅射法,通过优化成膜时的温度、功率、气体流量比、退火温度和膜层厚度等参数,以XRD,HR-TEM,NBED和EDS进行表征,研究制备结晶IGZO的工艺参数及其对薄膜晶体管(TFT)电性的影响。结果表明,当IGZO膜层厚度达到3000A以上时结晶效果明显,且不受其他因素影响;成膜功率对IGZO结晶现象有加强作用,功率越高越易结晶;成膜温度和氧气/氩气(O2/Ar)气体比例对IGZO结晶影响不大;成膜完成后经过600℃的退火处理可有效地促进IGZO的再结晶。通过优化IGZO成膜条件,制备出迁移率达29.6 cm^2/(V·s)的背沟道刻蚀结构IGZO TFT,比非晶IGZO TFT提高约3倍,显著地改善了IGZO TFT的电学特性。

A series of IGZO thin films were deposited using magnetron sputtering with different condition(substrate temperature,sputtering time,sputtering power,O2 flow rate,anneal temperature),and were characterized by X-ray diffraction(XRD),high resolution transmission electron microscope(HR-TEM),nano-beam electron diffraction(NBED)and energy dispersive spectrometer(EDS).The technological parameters and methods of preparing crystalline IGZO were studied.The results show that the thickness of the IGZO film has a significant effect on the crystallization of IGZO.When the thickness of the IGZO film is above 3000A,the crystallization effect is obvious,and is not affected by the film forming temperature,power and other factors.The crystallization of IGZO can be promoted effectively by 600℃annealing treatment after the film formation is completed,but the effect of film formation temperature and O2/Ar ratio on the crystallization of IGZO is not obvious.The crystalline IGZO active layer can be effectively prepared by adjusting the film thickness and annealing temperature.By optimizing the film forming conditions of IGZO,the back-channel etching structure IGZO TFT(thin film transistor)with mobility of 29.6 cm^2/(V·s)was prepared,which was about three times higher than that of amorphous IGZO TFT,and the electrical characteristics of IGZO TFT were significantly improved.