This paper describes methods of compensating environmental temperature and pressure dependence in a thermal conductivity type absolute humidity sensor using MEMS micro-heater. As a compensation method for environmental temperature dependence, we proposed a temperature compensation system that eliminates the environmental temperature dependence by a sub-heater formed around the micro-heater. In addition, as a method of compensating for the pressure dependence, a correction method by signal processing based on a model of free convective heat transfer in a horizontal plate was investigated. As a result of experimental evaluation, the effect of these compensation methods was verified.

The authors have investigated a high-sensitive hydrogen pressure sensor at low pressure range. In this paper, a new pressure sensor element composed of a zirconia base and a Cr-N thin film, which are not affected by hydrogen, was proposed. It was considered that such a sensor element could be placed into hydrogen gas and then detect directly the pressure variation in the pressure vessel. Also, the sensor element has a diaphragm structure with a reference pressure chamber in the base. Therefore, it was thought that the element could do the sensitive pressure sensing due to the Cr-N thin films which can detect a strain sensitively. The sensor elements mentioned above were fabricated and the experiments applying pressure to them were carried out. As a result, it was revealed that the sensor enabled stable and high-sensitive pressure detection in the low-pressure range less than 1MPa. The pressure sensor of this study can be expected as a new type of pressure sensor for hydrogen.

Advances in microfabrication technology have enabled electron beam lithography (EB lithography) systems to produce microfabrication on the order of tens of nanometers. Using this technology, we have fabricated nanogap electrodes that can generate large electric fields at low voltages. The gap between the tips of the fabricated electrodes is 100 nm, and the curvature of each tip is 50 nm. The device was confirmed to work as an electronic vacuum gauge, The device successfully measured vacuum from 10^-3 Pa to 1 Pa at the electrode voltage of 3 V.