本文選題：ZnO-TFT + 射頻磁控濺射�。� 參考：《深圳大學(xué)》2015年碩士論文

【摘要】：Zn O基薄膜晶體管(Thin Film Transistor,TFT)因其適合低溫生長、具有較高遷移率和透明性等特點,很大可能取代傳統(tǒng)的硅基TFT成為下一代顯示背板技術(shù)的主流。利用射頻磁控濺射法在室溫下制備Zn O薄膜時,未經(jīng)處理的薄膜載流子濃度較大、結(jié)晶質(zhì)量差,當(dāng)用作TFT器件的有源層時,會惡化器件的綜合性能或者使器件呈現(xiàn)耗盡型模式。因此,本論文通過優(yōu)化Zn O有源層的制備工藝和后期退火處理來調(diào)控有源層的輸運特性,從而提高器件的綜合性能。本論文采用底柵頂接觸的TFT器件結(jié)構(gòu),在Si O2/p-Si襯底上利用磁控濺射法制備Zn O薄膜作為器件的有源層,以重摻雜p型硅襯底作為器件的柵極,利用掩膜板蒸鍍法形成Al電極圖案作為器件的源漏電極,從而制備出完整的TFT器件。Zn O-TFT器件進行空氣退火后,器件的綜合性能隨退火溫度的升高先變好后變差。器件在400℃空氣退火后的綜合性能最佳,場效應(yīng)遷移率為2.7cm2/Vs,電流開關(guān)比達到5.0×105,閾值電壓為4.6V,亞閾值擺幅為1.0V/Dec。分析表明,空氣退火后,有源層中的吸附氧和Oi等受主類缺陷增加,有效降低了Zn O有源層中的載流子濃度,空氣退火同時改善了有源層的結(jié)晶質(zhì)量,減少了有源層和絕緣層界面處的表面缺陷態(tài)密度,結(jié)果柵壓對溝道電流的調(diào)控能力變強,從而提高了器件的性能。增加退火溫度到500℃,有源層中的氧相關(guān)受主類缺陷較多,它們對電子的散射和俘獲作用變得很強,表面缺陷態(tài)密度增大,導(dǎo)致器件的綜合性能下降。更高的退火溫度會對器件的絕緣層造成損傷,最終導(dǎo)致器件失效。不通氧制備的Zn O-TFT由于載流子濃度太高,器件的輸出曲線呈現(xiàn)出電阻效應(yīng)。在濺射氣氛中通入極少量的氧(O2:Ar=0.5:50sccm),有源層中氧相關(guān)受主類缺陷會增加,載流子濃度減小到一個相對合理的范圍,器件的性能相對較好,場效應(yīng)遷移率為0.05cm2/Vs、開關(guān)比為8.6×104、閾值電壓為28V、亞閾值擺幅為11V/Dec。當(dāng)通氧量增加時,氧相關(guān)受主類缺陷會過多,它們對電子的俘獲和散射作用變得很強,柵壓對溝道電流的調(diào)控能力變差,導(dǎo)致器件的綜合性能下降。在提高Zn O-TFT綜合性能方面,濺射氣氛中通入氧氣相比后期空氣退火處理而言效果要差。通氧制備的Zn O-TFT經(jīng)過N2退火后,一方面有源層中的氧相關(guān)受主缺陷減少,它們對電子的俘獲和散射作用減弱,同時薄膜的結(jié)晶質(zhì)量變好;另一方面Al電極與有源層的接觸得到改善,提高了電子的傳輸能力,從而使得器件的綜合性能提高。300℃退火后的器件綜合性能最優(yōu),場效應(yīng)遷移率為1.8cm2/Vs,開關(guān)比為1.43×106,閾值電壓為24V,關(guān)態(tài)電流為5×10-11A,亞閾值擺幅為5.5V/Dec。但隨退火溫度的繼續(xù)增加,載流子濃度進一步增大,器件的關(guān)態(tài)電流也會增大,開關(guān)比明顯下降。500℃退火后器件由增強型轉(zhuǎn)變?yōu)楹谋M型。
[Abstract]:Due to its characteristics of high mobility and transparency, ZnO-based TFT (thin Film Transistor TFT) is likely to replace the traditional silicon based TFT as the mainstream of the next generation display backplane technology due to its high mobility and transparency. When Zn O thin films were prepared by RF magnetron sputtering at room temperature, the untreated thin films were characterized by high carrier concentration and poor crystallization quality. When used as active layers of TFT devices, the comprehensive properties of TFT devices would be deteriorated or the devices would exhibit depleted mode. Therefore, in this thesis, the transport characteristics of Zno active layer can be adjusted by optimizing the preparation process of Zno active layer and post-annealing treatment, so as to improve the comprehensive performance of the device. In this thesis, ZnO thin films are fabricated on Sio _ 2 / p-Si substrate by magnetron sputtering method, and heavily doped p-type silicon substrate is used as the gate of the device. The Al electrode pattern was formed by the mask plate evaporation method as the source and leakage electrode of the device, and the integrated properties of the TFT device, ZnO-TFT device, after air annealing, first improved and then deteriorated with the increase of annealing temperature. After annealing at 400 鈩，

本文編號：2065970