Thin film - Hakumaku

This refers to a sample with a thickness of 1 nm to 0.1 μm that is used as a sample for a transmission electron microscope. Some researchers call anything thicker than that a thick film, but even a thickness of 100 μm can be called a thin film, so there is no strict definition. However, anything over 1 mm is not a film but a bulk (mass). As electronic devices become lighter, the development of thin-film electrodes and thin-film semiconductors has progressed, and the term thin film has come to be used in place of the traditional terms metal foil and artificial membrane. LB films, which are closely related to biological membranes, are also a type of thin film. A vacuum device is required to create a thin film from the gas phase, and the degree of vacuum varies depending on the desired thin film structure. Methods include vacuum deposition (10 ⁻⁴ Pa, island structure), sputtering (0.1 to 10 Pa, polycrystallization), and chemical vapor deposition (0.1 to 1 Pa, single crystallization). In addition to the above, methods such as plasma polymerization and molecular beam epitaxy can be used to create thin films of organic compounds. In addition, methods for fabricating from the liquid phase include the LB method mentioned above and anodic oxidation for creating oxide films, and the characteristics of each are utilized along with more conventional methods such as solution coating and electroplating.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

透過型電子顕微鏡の試料となる1 nm から0.1 μm の厚さの試料をいう．それ以上は厚膜とよぶ研究者もいるが，100 μm でも薄膜とよぶこともあり，厳密に定義されているわけではない．ただし，1 mm 以上は膜ではなくバルク(かたまり)である．電子機器の軽量化に伴い，薄膜電極，薄膜半導体などの開発が進み，薄膜という用語が従来の金属はくや人工膜にかわって用いられるようになった．生体膜に関連深いLB膜も薄膜の一種である．薄膜を気相から作製するには真空装置を必要とし，目的とする薄膜構造によって真空度も違ってくる．真空蒸着法(10^－4 Pa，島状構造)，スパッタリング法(0.1～10 Pa，多結晶化)，化学蒸着法(0.1～1 Pa，単結晶化)などがある．有機化合物の薄膜をつくるには，上述のほかに，プラズマ重合法や分子線エピタキシー法などがある．また，液相から作製する方法には，上述のLB法や酸化膜をつくるための陽極酸化法などがあり，従来からの溶液塗布や電気めっきなどとともに，それぞれの特徴が利用されている．

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