Review of recent progresses on flexible oxide semiconductor thin film transistors based on atomic layer deposition processes

Abstract

The current article is a review of recent progress and major trends in the field of flexible oxide thin film transistors (TFTs), fabricating with atomic layer deposition (ALD) processes. The ALD process offers accurate controlling of film thickness and composition as well as ability of achieving excellent uniformity over large areas at relatively low temperatures. First, an introduction is provided on what is the definition of ALD, the difference among other vacuum deposition techniques, and the brief key factors of ALD on flexible devices. Second, considering functional layers in flexible oxide TFT, the ALD process on polymer substrates may improve device performances such as mobility and stability, adopting as buffer layers over the polymer substrate, gate insulators, and active layers. Third, this review consists of the evaluation methods of flexible oxide TFTs under various mechanical stress conditions. The bending radius and repetition cycles are mostly considering for conventional flexible devices. It summarizes how the device has been degraded/changed under various stress types (directions). The last part of this review suggests a potential of each ALD film, including the releasing stress, the optimization of TFT structure, and the enhancement of device performance. Thus, the functional ALD layers in flexible oxide TFTs offer great possibilities regarding anti-mechanical stress films, along with flexible display and information storage application fields.

Recent advances, design guidelines, and prospects of flexible organic/inorganic thermoelectric composites

“…[75][76][77][78] At present, the preparation of inorganic thermoelectric materials by ALD, including Bi 2 Te 3 , Sb 2 Te 3 , Bi 2 Se 3 , ZnO and TiO 2 , has been reported in the literature. [79][80][81][82] Because the ALD process can be conducted under steady voltage and low temperature, there are fewer restrictions on the substrate, and this technique may be highly competitive in the field of flexible material preparation [83][84][85] and in the incorporation of inorganic thermoelectric materials into textile materials to expand their use in wearable flexible thermoelectric materials. 86 Molecular layer deposition (MLD) is another technique similar to ALD that uses sequential, self-limiting reactions to deposit thin films in molecular units.…”

Atomic layer deposition for quantum dots based devices

“…ALD has been extensively implemented into semiconducting processes in the past decade 37,38 . It is suitable to grow high-quality dielectric and semiconductor on different substrate even including the porous and high-aspect ratio substrates [39][40][41][42] , which has been widely used in areas of thin film solar cell, photodetectors and other electronic devices [43][44][45][46] . Besides, ALD is also a powerful method in thin film encapsulations for flexible electronics, due to the advantages of free pin-hole, excellent conformality and precise nanoscale thickness control on large area [47][48][49] .…”

Recent advances in mechanism investigation of atomic layer deposition by <italic>in situ</italic> photoelectron spectroscopy

“…目前, ALD技术已在 微电子领域得到了广泛应用, 包括用于制备微处理器 中的晶体管栅介电层 [ 5 ] 、集成电路中的互连籽晶 层 [5] 、动态随机存储器(DRAM)和3D NAND器件结 构中的介电层等 [6,7] . 同时, ALD技术也被广泛应用于 微纳机电系统 [5,8] 、显示与发光 [5,9,10] 、光伏 [11~13] 、能 源存储 [14~18] 、催化与电催化 [19~23] 、传感器 [24,25] 、表 面防腐 [5,26,27] 、太空防护 [28] 以及药物缓释 [29] ; ALD沉积薄 膜的厚度由周期数精确控制, 因此可从原子尺度精确 控制薄膜的厚度; ALD生长温度一般较低(室温至 400℃), 可用于在温度敏感的基底材料(如有机材料) 上沉积薄膜 [24] ; ALD沉积薄膜的重复性好, 适用于大 面积薄膜的制备.…”