Since the first report of amorphous In–Ga–Zn–O based thin film transistors,interest in oxide semiconductors has grown.They offer high mobility,low off-current,low process temperature,and wide flexibility for compos...Since the first report of amorphous In–Ga–Zn–O based thin film transistors,interest in oxide semiconductors has grown.They offer high mobility,low off-current,low process temperature,and wide flexibility for compositions and processes.Unfortunately,depositing oxide semiconductors using conventional processes like physical vapor deposition leads to problematic issues,especially for high-resolution displays and highly integrated memory devices.Conventional approaches have limited process flexibility and poor conformality on structured surfaces.Atomic layer deposition(ALD)is an advanced technique which can provide conformal,thickness-controlled,and high-quality thin film deposition.Accordingly,studies on ALD based oxide semiconductors have dramatically increased recently.Even so,the relationships between the film properties of ALD-oxide semiconductors and the main variables associated with deposition are still poorly understood,as are many issues related to applications.In this review,to introduce ALD-oxide semiconductors,we provide:(a)a brief summary of the history and importance of ALD-based oxide semiconductors in industry,(b)a discussion of the benefits of ALD for oxide semiconductor deposition(in-situ composition control in vertical distribution/vertical structure engineering/chemical reaction and film properties/insulator and interface engineering),and(c)an explanation of the challenging issues of scaling oxide semiconductors and ALD for industrial applications.This review provides valuable perspectives for researchers who have interest in semiconductor materials and electronic device applications,and the reasons ALD is important to applications of oxide semiconductors.展开更多
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 accur...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.展开更多
基金supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (NRF-2020M3H4A3081867)the industry technology R&D program (20006400) funded by the Ministry of Trade,Industry and Energy (MOTIE, Korea)+2 种基金the project number 20010402 funded by the Ministry of Trade,Industry and Energy (MOTIE, Korea)the Industry Technology R&D program (#20010371) funded by the Ministry of Trade,Industry and Energy (MOTIE, Republic of Korea)the Technology Innovation Program (20017382) funded By the Ministryof Trade,Industry and Energy (MOTIE, Korea)
文摘Since the first report of amorphous In–Ga–Zn–O based thin film transistors,interest in oxide semiconductors has grown.They offer high mobility,low off-current,low process temperature,and wide flexibility for compositions and processes.Unfortunately,depositing oxide semiconductors using conventional processes like physical vapor deposition leads to problematic issues,especially for high-resolution displays and highly integrated memory devices.Conventional approaches have limited process flexibility and poor conformality on structured surfaces.Atomic layer deposition(ALD)is an advanced technique which can provide conformal,thickness-controlled,and high-quality thin film deposition.Accordingly,studies on ALD based oxide semiconductors have dramatically increased recently.Even so,the relationships between the film properties of ALD-oxide semiconductors and the main variables associated with deposition are still poorly understood,as are many issues related to applications.In this review,to introduce ALD-oxide semiconductors,we provide:(a)a brief summary of the history and importance of ALD-based oxide semiconductors in industry,(b)a discussion of the benefits of ALD for oxide semiconductor deposition(in-situ composition control in vertical distribution/vertical structure engineering/chemical reaction and film properties/insulator and interface engineering),and(c)an explanation of the challenging issues of scaling oxide semiconductors and ALD for industrial applications.This review provides valuable perspectives for researchers who have interest in semiconductor materials and electronic device applications,and the reasons ALD is important to applications of oxide semiconductors.
基金supported by the National Research Foundation of Korea(NRF)(No.NRF-2017RID1A1B03034035)the Ministry of Trade,Industry&Energy(No.#10051403)the Korea Semiconductor Research Consortium
文摘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.