藉由爐管退火在氮氣與氧氣環境下製備 P 型氧化錫薄膜電晶體之探討

Abstract

近幾年來，由於相對傳統非晶矽薄膜電晶體，氧化物半導體薄膜電晶體管由於可以使用於大量生產以及具備更高的性能和穩定性而受到關注。然而，其中大多數已被使用n型氧化物薄膜電晶體的設計和在各種顯示器或在柔性電子產品，而p型氧化物薄膜電晶體較少被研究, 利用兩個n型和p型電晶體的互補型邏輯電路相較於只使用一種類型的電晶體有較多的優點,例如低功率和簡單性的電路設計。高性能的p型氧化物薄膜電晶體是高度期望的，這樣的低功耗的高性能互補電路可以和氧化物薄膜電晶體或有源矩陣有機發光二極管（AMOLED）顯示器一起使用。 在這次的研究論文裡，我們採用了電子槍蒸鍍系統來沉積我們的氧化錫薄膜當作主動層。使用不同的溫度對此薄膜進行退火來處理通道層，以實現p型氧化錫薄膜電晶體，並探討退火對於p型氧化錫薄膜電晶體的電特性影響。我們也對薄膜的材料特性作分析，從X射線光電子能譜儀及X光繞射儀的數據顯示經過蛻蘳處理後的氧化錫的相位部分從一氧化錫變成二氧化錫，且隨著退火溫度上升而增加，通道層為20奈米厚的氧化錫薄膜電晶體在退火350度時通入氮氣和氧氣處理30分鐘的條件下有最好的特性。 氧化錫薄膜電晶體在退火350度時通入氮氣和氧氣處理30分鐘的條件下的場效遷移率有0.883 cm2/(V·S)，次臨界擺幅 1.15 V/decade，開關電流比 1.01×103。由實驗結果顯示，利用爐管退火在氮氣和氧氣環境下處理，能實現P型氧化錫的特性，電流開關比都有達先前文獻之水準，具有極佳的發展潛力。

In recent years, compared with the conventional a-Si TFTs, Thin-film transistors (TFTs) based on oxide semiconductors have drawn much attention because of there having higher performance and stability for mass production. However, most of them have been designed using only n-type oxide TFTs and have been used in various displays or in flexible electronics, only a few p-type oxides have been reported for TFTs, The complementary logic circuits exploiting both n- type and p-type transistors have several advantages over circuits with only one type transistors, such as the low power consumption and the simplicity in the circuit design. High-performance p-type oxide TFTs are highly desired so that low-power high-performance complementary circuits can be utilized by oxide TFTs or the active-matrix organic light- emitting diode (AMOLED) displays. In this investigation, we used E-beam Evaporation system to deposit our SnO active layer. The as-deposited films were subjected to postdeposition annealing process at different temperatures. We have investigated the effects of annealing on the electrical performance of the p-type tin oxide thin-film transistors. From the x-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD) data, it is demonstrated that the phase of tin oxide partially transforms from SnO to SnO2 with an annealing process, and it accelerates as the annealing temperature increases. The electrical performance of the p-type tin oxide TFT with a channel thickness of 20 nm exhibits much improved electrical performance when annealed with N2+ O2 350°C for 30 min. The electrical characteristics of SnOX TFTs with active layer annealed with N2+ O2 350°C for 30 min as follow: the mobility was 0.883 cm2/V·S, the subthreshold swing was 1.15 V/decade, and the Ion/Ioff was 1.01×103. The experiment results show that furnace annealing in oxygen and nitrogen ambient could realize p-type SnOx TFTs. The electrical characteristics reach the level of previous literatures and have great potential.