Micro-miniature ionizer for gas sensor applications and method of making micro-miniature ionizer
US5747815A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 1996 |
| Grant date | May 5, 1998 |
| Priority date | — |
| Expiry date | Jul 24, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J49/288
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A gas ionizer is provided for use in a solid state mass spectrograph for analyzing a sample of gas. The gas ionizer is located in a cavity provided in a semiconductor substrate which includes an inlet for introducing the gas to be analyzed. The gas ionizer ionizes the sample of gas drawn into the cavity through the inlet to generate an ionized sample gas. The gas ionizer generates energetic particles or photons which bombard the gas to be sampled to produce ionized gas. The energetic particles or photons can be generated by reverse-bias p-n junctions, radioactive isotopes, electron discharges, point emitters, and thermionic electron emitters. A layer of cesium chloride or cesium iodide having a low work function is formed on top of the reverse-bias p-n junction gas ionizer to increase current emitted per junction area and so that the gas ionizer can be exposed to atmospheric oxygen during storage and can operate in reduced atmosphere with no additional treatments. The cesium chloride layer and the cesium iodide layer do not readily electromigrate. A fabrication process of the mass spectrograph includes using plural masks to ensure proper exposure of resist on both flat and wall sur…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.