We propose a high-performance porous metal–insulator–metal-type capacitive humidity sensor based on a functional polymer mixed with TiO₂ microparticles subjected to inductively coupled plasma (ICP) and reactive-ion etching (RIE) treatments. The humidity sensor is composed of a porous top electrode, a TiO₂-containing functional polymer humidity-sensitive layer subjected to two types of oxygen plasma treatment, a bottom electrode, and a glass substrate. The initial O₂ ICP dry-etching utilizes higher intensity plasma for deep etching in the inlet holes on the top electrode to increase the contact area and shorten the vapor absorption path, thereby yielding high sensitivity and low hysteresis. Further, the RIE treatment leads to roughening of the polymer etching surface and further improving the performance of the humidity sensor. The functional polymer mixed with TiO₂ microparticles exhibits excellent hysteresis over a wide humidity sensing range. The fabricated sensors are tested at various relative humidity (RH) values, achieving an ultra-low hysteresis of 0.64% RH at 60% RH, a high sensitivity of 1.24 pF/% RH, a fast response time of less than 25 s, good temperature dependence, and a stable capacitance value with a maximum error rate of 0.15% over 120 h of continuous testing.

我们提出了一种高性能多孔金属-绝缘体-金属型电容式湿度传感器，该传感器基于功能性聚合物与TiO ₂微粒混合后进行了感应耦合等离子体（ICP）和反应离子刻蚀（RIE）处理。湿度传感器由多孔的顶部电极，经过两种氧等离子体处理的含TiO ₂的功能性聚合物湿度敏感层，底部电极和玻璃基板组成。初始O ₂ICP干蚀刻利用较高强度的等离子体对顶部电极上的入口孔进行深蚀刻，以增加接触面积并缩短蒸气吸收路径，从而获得高灵敏度和低滞后性。此外，RIE处理导致聚合物蚀刻表面的粗糙化并进一步改善了湿度传感器的性能。与TiO ₂混合的功能聚合物微粒在很宽的湿度感应范围内都具有出色的滞后性。所制造的传感器在各种相对湿度（RH）值下进行测试，在60％RH时实现0.64％RH的超低磁滞，在1.24 pF /％RH时具有高灵敏度，不到25 s的快速响应时间，良好温度依赖性和稳定的电容值，在120 h的连续测试中，最大误差率为0.15％。