Microvacuum sensor having an expanded sensitivity range

US5597957A · kind A · utility

Assignee

• Heimann Optoelectronics GmbH · DE

Inventors

• Joerg Schieferdecker · Wiesbaden, DE
• Friedemann Voelklein · Jena, DE

Key dates

• Filing date: Dec 21, 1994
• Grant date: Jan 28, 1997
• Expiry date: Dec 21, 2014

Classification

• Technology area (CPC G): Physics
• CPC primary: G01L21/10
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A microvacuum sensor has an expanded sensitivity range, wherein a thin membrane having poor thermal conductivity is freely suspended on a semiconductor single-crystal. A thin metallic heating layer, preferably of aluminum, is arranged on the membrane. The membrane surface is suspended by at least one web of the membrane material. The heating layer has an extremely low emissivity of less than 0.1 in the near infrared range. A film resistor having the same temperature coefficient as the metallic heating layer is arranged on the sensor chip in the region of the solid silicon for temperature compensation of temperature fluctuations. Members having a planar mirrored wall are arranged parallel to the surfaces of the membrane at a spacing of less than 5 .mu.m from the membrane. These members act as a heat sink relative to the membrane. Gas from the environment of the sensor can freely circulate between the membrane and the wall surfaces.