Fabrication of Microactuators Utilizing Sputter-deposited Ti-Ni Shape Alloy Thin Films

在硅衬底上制备了Ti-Ni形状记忆合金薄膜。对它们进行了形状记忆，并测量了它们的转变特性。使用的是钛镍靶材。通过广泛改变热处理温度和时间进行形状记忆，以考察热处理条件对相变特征的影响。随着热处理温度的升高，相变温度也随之升高。采用微机械加工技术，在Si基片上涂覆一层Ti-Ni薄膜，制成微驱动器结构。驱动器由2.0微米厚的Ti-Ni膜和1.0微米厚的SiO_2膜组成。在加热和冷却过程中，利用Azer光束技术测量了致动器的高度。致动器冷却时达到几十微米，加热时变平，并在随后的热循环中重复运动。MS为340K，而AS为360K，它们远高于室温，因此由于良好的冷却条件，获得了50赫兹的响应。制备了各种尺寸的致动器，并测量了它们的致动器特性，尺寸在100到1400微米之间。驱动距离与执行器大小呈线性相关。这意味着通过利用这些致动器，各种应用将成为可能。

Ti-Ni shape memory alloy thin films have been made on Si substrates. They were shape memorized and their transformation characteristics were measured. A Ti-Ni target was used. Shape memorization was conducted by widely varying heat-treatment temperature and time in order to investigate the effect of heat-treatment condition on the transformation characteristics. The transforamtion temperatures increased eith increasing heat-treatment temperature.Si substartes coated by a Ti-Ni film were.micromachined to fabricate microactuator structures. The actuator is composed of a 2.0 micrometer thick Ti-Ni film and a 1.0 micrometer thick SiO_2 film. The hight of the actuators was measured during heating and cooling by using a |azer beam technique. The actuator reached several tens micrometer upon cooling and became flat upon heating, and the movement was repeated by following thermal cycling. The Ms was 340 K, while the As was 360 K. They are well above the room temperature so that a 50 Hz response was achieved due to a good coolingjate. Variety of sizes of actuators were prepared and their actuator characteristics were measured, the size beins ranged between 100 and 1400 micrometers. The actuation distance was linealy corelated with the actuator size. This means that variety of applications will be possible by utilizing these actuators.