本文選題：IGZO-TFT + 磁控濺射�。� 參考：《電子科技大學》2015年碩士論文

【摘要】：非晶銦鎵鋅氧化物(Indium Gallium Zinc Oxide,IGZO)具有遷移率高、均一性好等特點,并且在可見光區(qū)有較高的光透過率,有望實現全透明以及柔性顯示,是新一代氧化物薄膜晶體管中應用最廣泛,也是最主流的有源層材料。本論文采用直流磁控濺射方法制備了IGZO薄膜并以其為有源層制備了IGZO-TFT,具體的研究內容包括:(1)采用直流磁控濺射方法制備IGZO薄膜,研究了濺射功率、濺射時間對薄膜的可見光范圍內光學透過率的影響。結果表明直流磁控濺射制備出的IGZO薄膜的可見光區(qū)光透過率基本保持在80%左右,在濺射功率為180 W,濺射時間為200 s下制備的薄膜光透過率高達89.73%。然后利用SEM、AFM觀察并分析了不同濺射功率、不同濺射腔氣壓和不同氧分壓下制備得到的IGZO薄膜表面形貌,SEM圖像表明濺射功率在180-200 W范圍內,2 mTorr濺射腔氣壓下,IGZO薄膜表面平整,缺陷較少;AFM圖像表明隨著氧分壓的增大,薄膜表面越平整,粗糙度越小,并且在襯底上旋涂一層有機溶液后再沉積IGZO薄膜的粗糙度要比在襯底上直接沉積的小很多。最后通過XRD測試驗證了直流磁控濺射的IGZO薄膜為非晶態(tài)。(2)利用旋涂法分別制備以PMMA、PVA為絕緣層,直流磁控濺射IGZO為有源層的底柵頂接觸型IGZO-TFT器件。研究了氧分壓、緩沖層、絕緣層厚度以及退火處理對IGZO-TFT器件性能的影響。對于以PMMA為絕緣層、IGZO為有源層的TFT器件,研究結果表明氧分壓增加會導致載流子遷移率先增大后減小,氧分壓為1.2%時,載流子遷移率最大,為0.84 cm2·V-1·s-1。采用低功率磁控濺射超薄IGZO緩沖層(5 nm)能降低電子陷阱和薄膜粗糙度,優(yōu)化絕緣層和有源層的界面態(tài),提升有源層的成膜質量。對于以PVA為絕緣層、IGZO為有源層的TFT器件,研究結果表明隨著絕緣層厚度的增加,載流子遷移率和電流開關比均呈現增大的趨勢,并且器件的性能要優(yōu)于以PMMA作為絕緣層時的。絕緣層厚度為800nm時,TFT器件性能最好,載流子遷移率為11.4 cm2·V-1·s-1,電流開關比為9.6×102,閾值電壓為9.7 V。研究還表明經過退火處理的器件性能要比未退火處理的器件性能好,退火溫度在200℃時最佳,此時器件的載流子遷移率為24.8 cm2·V-1·s-1,電流開關比為3.5×103,閾值電壓為7.3 V。
[Abstract]:Indium Gallium Zinc oxide (IGZO) has the characteristics of high mobility, good uniformity and high optical transmittance in the visible region. It is expected to achieve full transparency and flexible display. It is the most widely used in the new generation of oxide thin film transistors. Is also the most mainstream active layer material. In this thesis, IGZO thin films were prepared by DC magnetron sputtering and IGZO-TFT thin films were prepared by using them as active layers. The specific research contents include: (1) DC magnetron sputtering method was used to fabricate IGZO thin films, and the sputtering power was studied. The influence of sputtering time on the optical transmittance in the visible range of the film. The results show that the optical transmittance of the IGZO thin films prepared by DC magnetron sputtering is about 80% in the visible region, and the transmittance of the films prepared at the sputtering power of 180W and the sputtering time of 200s is as high as 89.73g. Then the surface morphologies of IGZO films prepared under different sputtering power, different sputtering chamber pressure and different oxygen partial pressure were observed and analyzed by SEMMA-AFM. The results showed that the surface of IGZO thin films was flat in the sputtering power range of 180-200W / 2 mTorr sputtering cavity pressure. The results show that with the increase of oxygen partial pressure, the surface of the IGZO films is flat and the roughness is smaller, and the roughness of the IGZO films deposited on the substrates is much smaller than that on the substrates after spin-coating with an organic solution. Finally, the XRD test shows that the IGZO films deposited by DC magnetron sputtering are amorphous. (2) the bottom gate top contact IGZO-TFT devices with PMMA-PVA as insulation layer and DC magnetron sputtering IGZO as active layer are fabricated by spin-coating method. The effects of oxygen partial voltage, buffer layer, insulation thickness and annealing treatment on the performance of IGZO-TFT are studied. For TFT devices with PMMA as the insulating layer and IGZO as the active layer, the results show that the increase of oxygen partial pressure will lead to the increase of carrier migration first and then decrease, and the maximum carrier mobility of 0.84 cm2 V-1 s-1 when oxygen partial voltage is 1.2. The ultra-thin IGZO buffer layer (5 nm) prepared by low power magnetron sputtering can reduce the electron trap and the roughness of the film, optimize the interface state between the insulating layer and the active layer, and improve the film forming quality of the active layer. For TFT devices with PVA as the insulator and active layer, the results show that the carrier mobility and the current-switching ratio increase with the increase of the thickness of the insulating layer, and the performance of the device is better than that of the TFT device with PMMA as the insulator. When the thickness of insulation layer is 800nm, the device has the best performance, the carrier mobility is 11.4 cm2 V-1 s-1, the current-switching ratio is 9.6 脳 102, and the threshold voltage is 9.7 V. The results also show that the annealed device has better performance than the unannealed device. The annealing temperature is 200 鈩，

本文編號：1984668