Process for depositing a surface-wide layer through a mask and optionally closing said mask

US5786235A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Ignaz Eisele · Icking, DE
• Bertrand Flietner · Hopewell Junction, US
• Josef Lechner · Feldkirchen-Westerham, DE

Key dates

• Filing date: Oct 31, 1995
• Grant date: Jul 28, 1998
• Expiry date: Oct 31, 2015

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N27/4143
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

As a result of deposition from different directions through a mask, a layer can be applied last in a surface-wide form underneath the mask. In this arrangement, the mask is separated by a cavity from the base in the coating region and is firmly joined to it outside the coating region. This process is advantageous, in particular, for the SGFET (suspended-gate field-effect transistor) used as gas sensor. In this process, the mask also forms the gate and the sensitive layer is not subjected to any further process after the deposition. The mask may then remain open or be closed by depositing such a large amount that the openings in the mask are grown over laterally, or by depositing an additional layer at an oblique angle. This process is also suitable for producing micromechanical membranes.