Patent ID: 8141429
Filing Date: 2012-03-27
Classification: G01L,Y10T

Abstract:
1. A capacitive pressure sensor comprising: i) a housing defining an interior sensing chamber and a pressure port which extends from an exterior of the housing to the interior sensing chamber; ii) a sapphire diaphragm disposed within the interior sensing chamber of the housing and having a first electrode formed on a central portion thereof, the central portion of the diaphragm and the first electrode being adapted and configured to deflect in response to pressure variations encountered within interior sensing chamber; and iii) a sapphire substrate disposed within the interior sensing chamber of the housing, wherein a peripheral portion of the sapphire substrate is fused to the sapphire diaphragm to form a sapphire stack and a reference chamber is defined between the central portion of the sapphire diaphragm and a central portion of sapphire substrate, the sapphire substrate having a second electrode formed on its central portion opposite the first electrode, wherein prior to fusing the sapphire diaphragm to the sapphire substrate, all contact surfaces are chemically treated and prepared using plasma activation, so as to create a bonding layer and to reduce the temperature required for the fusion.