以原子層沈積法製作高品質氧化鋅薄膜及其元件之應用

本文章主要探討以原子層沈積法沈積高品質氧化鋅薄膜，藉由原子層沈積法的均勻性及高階梯覆蓋性，製作增強型氧化鋅透明薄膜電晶體，並改變不同溫度沈積氧化鋅通道層及改變氧化鋅含微量鋁金屬之鋁含量，並對不同閘源極電壓下之汲源極電流－汲源極電壓關係、固定汲源極電壓之汲源極電流－閘源極電壓關係與元件照光穩定性進行分析。在變溫沈積通道層方面，由於以原子層沈積法沈積氧化鋅薄膜，會因為基板溫度變化，對薄膜的濃度、阻值及載子移動率會有影響，而薄膜電晶體則會因為薄膜濃度太大導致沒有電晶體特性。故本論文固定通道層厚度為25nm，以100℃為最佳沈積溫度，場效載子移動率達8.87cm^2/V-s，電流開關比(I(下標 on)/I(下標 off))為10^6。探討通道層氧化鋅摻雜不同微量鋁之比例，分別為30(DEZn):1(TMA)、20:1、15:1，其中以20:1的比例為最佳條件，場效載子移動率達73.4cm^2/V-s，電流開關比(I(下標 on)/I(下標 off))為106，而摻雜比例到的15:1時，則因為薄膜濃度過高，元件無飽和現象。

關鍵字

原子層沈積法；透明薄膜電晶體；氧化鋅

並列摘要

Highly transparent ZnO based (pure and Al slightly doped ZnO) thin films were prepared by Atomic Layer Deposition (ALD). The deposited ZnO based films exhibited large area uniformity and high step coverage. The obtained films of a thickness of 25 nm were used as the active channel layers to fabricate enhancement-mode transparent thin film transistors. In the work different deposition temperatures and Al doping amount were used to deposit ZnO films. The fabricated TFTs were characterized and the resultant IDS-VDS and IDS-VGS curves were analyzed, as well as the stability of the devices under illumination of light with different wavelengths. It is found that the carrier concentration, resistivity and mobility were affected by the substrate temperature during the ALD deposition process of ZnO channel layers. It is noted that the fabricated TFTs would lose properties of transistor when the carrier concentration is too high. The experiments revealed that the deposition temperature was optimized to be about 100. The TFTs fabricated at this temperature exhibited a field effect mobility of 8.87 cm^2/V-s and current on/off ratio (I(subscript on)/I(subscript off)) up to 10^6. The effects of Al doping level in ZnO films were studied, in which various ratios of DEZn and TMA, 30:1, 20:1 and 15:1, were used for the film deposition. The best condition among these ratios is 20:1, under which the resultant TFTs showed that its field effect mobility can reach to 73.4 cm^2/V-s and current on/off ratio (I(subscript on)/I(subscript off)) up to 106. As the doping ratio reaching 15:1, the carrier concentration was too high for the device reaching the saturation situation.

並列關鍵字

Atomic layer deposition ； Transparence thin film transistors ； ZnO

國際替代計量

以原子層沈積法製作高品質氧化鋅薄膜及其元件之應用

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