The paper presents a MEMS-type ionization vacuum sensor fabricated in batch on 4-in wafers based on through glass via (TGV) technology. The utilization of TGV technology enables the sensor to exhibit a compact three-layer stacked structure, where an yttrium oxide thermionic electron emitter and an ion collector are assembled in the same TGV layer. In addition to the compact dimensions of only 14×9×3.6 mm ³ , the wafer-scale fabricated sensors exhibit a wide measurement range from 1×10 ^-4 Pa to 40 Pa, an improved sensitivity of 0.019 Pa ^-1 and a production yield of 94%. All these results imply the promising applications of our sensors for vacuum measurement, especially for in-situ vacuum monitoring in vacuum electronic devices.

Vacuum triodes have been scaled down to the microscale on a chip by microfabrication technologies to be vacuum transistors. Most of the reported devices are based on field electron emission, which suffer from the problems of unstable electron emission, poor uniformity, and high requirement for operating vacuum. Here, to overcome these problems, a vacuum transistor based on Field-Assisted thermionic emission from individual carbon nanotubes is proposed and fabricated using microfabrication technologies. The carbon nanotube vacuum transistor exhibits an ON/OFF current ratio as high as 10⁴ and a subthreshold slope of ~4 V·dec⁻¹. The gate controllability is found to be strongly dependent on the distance between the collector electrodes and electron emitter, and a device with the distance of 1.5 μm shows a better gate controllability than that with the distance of 0.5 μm. Benefiting from Field-Assisted thermionic emission mechanism, electric field required in our devices is about one order of magnitude smaller than that in the devices based on field electron emission, and the surface of the emitters shows much less gas molecule absorption than cold field emitters. These are expected to be helpful for improving the stability and uniformity of the devices.

The paper presents a MEMS-type ionization vacuum sensor based on electron emission from an on-chip thermionic electron source. The sensor employs a multilayer-stacked structure fabricated by anodic bonding technology, showing overall dimensions of 12 × 12 × 3.3 mm ³ . Because of the efficient and stable electron emission of an yttrium oxide electron source, the sensor exhibits a wide linear response range from 1 × 10 ^-4 Pa to 100 Pa with a good repeatability, covering both high and medium vacuum regimes. It provides a new miniature vacuum sensor with a wide measurement range.

An ON-chip vacuum transistor based on electron emission from SiOx tunneling diodes formed at the side surface of a thin SiO2 film is proposed, where electrons transport in the vacuum channel between the electron emitter and collector electrode is modulated by an underneath gate electrode. The device performances are studied by the finite element simulation method. An ON/OFF current ratio up to 105 and a subthreshold slope of ~500 mV/dec are obtained by simulation. Experimentally, a vacuum transistor based on SiOx tunneling diodes in a surrounding structure is fabricated, achieving an ON/OFF current ratio of 104 and a subthreshold slope of ~5 V/dec. The performance degradation in experiments is mainly attributed to unoptimized device structures.

In this work, we report a micro-Pirani vacuum sensor based on super-aligned carbon nanotube (CNT) films. The devices are batch fabricated on silicon wafers utilizing simple microfabrication process, demonstrating much higher capability of large-scale and efficient parallel manufacturing compared with the previous reported CNT Pirani sensors. Additionally, owing to the nanoscale diameter and excellent electrical and physical properties of CNT films, the upper pressure operating range is pushed up to several atmospheres (≈2.5×10 ⁵ Pa). And the devices exhibit good performance on reproducibility (standard deviation of <0.32%) and relatively high accuracy (relative error of 0.39% at 2×10 ⁴ Pa). All these results demonstrate the feasibility of our device as pressure sensors in future.

An on-chip vacuum triode based on thermionic electron emission from suspended super-aligned carbon nanotube films is realized via microfabrication technology.