退火工艺对薄膜铂电阻性能及微观结构的影响

The Effect of Annealing Process on the Properties and Microstructure of Thin-Film Platinum Resistors

摘要: 通过MEMS工艺在氧化铝陶瓷衬底上制备了薄膜铂电阻温度传感器，对薄膜铂电阻进行不同温度和时间的退火处理。结果表明，薄膜铂电阻在1000℃退火1 h后的TCR值达到最大值3654 ppm/℃，退火处理后样品的线性度和均匀性得到了显著提高；随着退火温度的升高，铂晶粒的尺寸不断增大，薄膜表面的凹坑和孔洞也逐渐得到“修复”，退火后薄膜的组织结构由疏松纤维状向等轴晶状转变，晶粒更倾向沿着[111]晶向择优生长，从而降低电阻率，提高铂薄膜的TCR。

Abstract: Thin-film platinum resistor temperature sensors were fabricated on alumina ceramic substrates using MEMS (Micro-Electro-Mechanical Systems) technology, and the thin-film platinum resistors were subjected to annealing treatments at different temperatures and durations. The results show that the Temperature Coefficient of Resistance (TCR) of the thin-film platinum resistor reaches a maximum value of 3654 ppm/˚C after annealing at 1000˚C for 1 h. Additionally, the linearity and uniformity of the samples are significantly improved after annealing. With the increase of annealing temperature, the size of platinum grains increases continuously, and the pits and holes on the film surface are gradually “repaired”. After annealing, the microstructure of the film transforms from a loose fibrous structure to an equiaxed crystalline structure, and the grains tend to grow preferentially along the [111] crystal orientation. This transformation reduces the resistivity and improves the TCR of the platinum thin film.