Application of hydrogen injection and oxidation to low temperature solution-processed oxide semiconductors

Abstract

Solution-processed oxide semiconductors are promising candidates for the low cost, large scale fabrication of oxide thin-film transistors (TFTs). In this work, a method using hydrogen injection and oxidation (HIO) that allows the low temperature solution processing of oxide semiconductors was demonstrated. We found that this method significantly decreases the concentration of residual species while improving the film densification. Additionally, enhanced TFT performance was confirmed following the use of processing temperatures as low as 300 °C. The proposed process is potentially applicable to the fabrication of a wide variety of solution-processed oxide semiconductors.

A Sustainable Approach to Flexible Electronics with Zinc‐Tin Oxide Thin‐Film Transistors

“…O 1s peaks analysis is presented in Figure , after deconvolution into three subpeaks centered at 530.4 (O I ), 531.7 (O II ), and 532.7 eV (O III ) using a Gaussian Lorentzian mixed function. These subpeaks can be attributed to O 2− ions surrounded by the metallic cations and other oxygen ions (O I ), O 2− ions in oxygen‐deficient regions (O II ), and loosely bound oxygen species at the surface, for example, CO 3 or adsorbed H 2 O (O III ) . Given the high surface sensitivity inherent to XPS technique, a detailed quantitative analysis of the films would require a tight control of the sample transfer between the sputtering tool and XPS and/or implementation of adequate Ar/Ar cluster ions surface cleaning procedures without inducing chemical changes to the specific sample under measurement (which can be challenging on low‐temperature deposited oxides, being thus out of the scope of this study.…”

“…O 1s peaks analysis is presented in [40,41] Given the high surface sensitivity inherent to XPS technique, a detailed quantitative analysis of the films would require a tight control of the sample transfer between the sputtering tool and XPS and/or implementation of adequate Ar/Ar cluster ions surface cleaning procedures without inducing chemical changes to the specific sample under measurement (which can be challenging on low-temperature deposited oxides, [36] being thus out of the scope of this study. O 1s peaks analysis is presented in [40,41] Given the high surface sensitivity inherent to XPS technique, a detailed quantitative analysis of the films would require a tight control of the sample transfer between the sputtering tool and XPS and/or implementation of adequate Ar/Ar cluster ions surface cleaning procedures without inducing chemical changes to the specific sample under measurement (which can be challenging on low-temperature deposited oxides, [36] being thus out of the scope of this study.…”

“…[13,14] The effect of hydrogen doping has been verified experimentally in IGZO and even ZTO TFTs via thermal treatments and/or deposition of insulator layers on top of the oxide semiconductor, [15][16][17] but again, always requiring temperatures not compatible with PEN foils. Therefore, having highperformance ZTO TFTs at low temperature requires both material selection (e.g., ZTO composition and dielectric material) and deposition processes to readily enable a low subgap density of states (DOS).…”

“…The work in this field by Körner et al suggests hydrogen incorporation in IGZO and ZTO as a strategy to achieve this objective, by reducing the density of deep level defects and also by contributing as a shallow donor . The effect of hydrogen doping has been verified experimentally in IGZO and even ZTO TFTs via thermal treatments and/or deposition of insulator layers on top of the oxide semiconductor, but again, always requiring temperatures not compatible with PEN foils. Furthermore, in ZnO‐based materials temperatures exceeding 220 °C can result in dissociation of substitutional hydrogen (H O ) into oxygen vacancies and interstitial hydrogen (H i ), which is known to be thermally unstable and mobile even at room temperature…”

Reliability enhancement in thin film transistors using Hf and Al co-incorporated ZnO active channels deposited by atomic-layer-deposition

“…To achieve the production of more enhanced oxide TFTs, there are lots of factors affecting the device characteristics of oxide TFTs, such as fabrication process conditions including post-annealing temperatures, 3,4 device structures, 5,6 gate insulators, 7,8 and semiconducting active compositions. [9][10][11] Among them, the material design of the active channel can be a powerful method to effectively control the device properties.…”