Background: Hydrogen sensors are micro/nano-structure that are used to locate hydrogen leaks. They are considered to have fast response/recovery time and long lifetime as compared to conventional gas sensors. In this paper, fabrication of sensitive capacitive-type hydrogen gas sensor based on Ni thin film has been investigated. The C-V curves of the sensor in different hydrogen concentrations have been reported.

Method: Dry oxidation was done in thermal chemical vapor deposition furnace (TCVD). For oxidation time of 5 min, the oxide thickness was 15 nm and for oxidation time 10 min, it was 20 nm. The Ni thin film as a catalytic metal was deposited on the oxide film using electron gun deposition. Two MOS sensors were compared with different oxide film thickness and different hydrogen concentrations.

Results: The highest response of the two MOS sensors with 15 nm and 20 nm oxide film thickness in 4% hydrogen concentration was 87.5% and 65.4% respectively. The fast response times for MOS sensors with 15 nm and 20 nm oxide film thickness in 4% hydrogen concentration was 8 s and 21 s, respectively.

Conclusion: By increasing the hydrogen concentration from 1% to 4%, the response time for MOS sensor (20nm oxide thickness), was decreased from 28s to 21s. The recovery time was inversely increased from 237s to 360s. The experimental results showed that the MOS sensor based on Ni thin film had a quick response and a high sensitivity.

背景：氢传感器是用于定位氢泄漏的微/纳米结构。与传统的气体传感器相比，它们被认为具有快速响应/恢复时间和长寿命。本文研究了基于Ni薄膜的灵敏电容式氢气传感器的制作。已经报道了传感器在不同氢气浓度下的 CV 曲线。

方法：在热化学气相沉积炉（TCVD）中进行干氧化。氧化时间为 5 分钟，氧化层厚度为 15 nm，氧化时间为 10 分钟，氧化层厚度为 20 nm。使用电子枪沉积将作为催化金属的 Ni 薄膜沉积在氧化膜上。比较了两个具有不同氧化膜厚度和不同氢浓度的 MOS 传感器。

结果：两种氧化膜厚度分别为15 nm和20 nm的MOS传感器在4%氢气浓度下的最高响应分别为87.5%和65.4%。氧化膜厚度为 15 nm 和 20 nm 的 MOS 传感器在 4% 氢浓度下的快速响应时间分别为 8 秒和 21 秒。

结论：通过将氢浓度从 1% 增加到 4%，MOS 传感器（20nm 氧化物厚度）的响应时间从 28s 减少到 21s。恢复时间从 237 秒反向增加到 360 秒。实验结果表明，基于Ni薄膜的MOS传感器响应速度快，灵敏度高。