Methods of fabricating integrated transducer assemblies

The method of fabricating a transducer comprising the steps of:

• a. growing a thin layer of silicon dioxide on a diaphragm of silicon,
• b. etching said layer according to a contact pattern,
• c. diffusing a contact pattern on said diaphragm, said process causing an undesired transition to appear at said etched portion,
• d. growing a thick layer of silicon dioxide on said pattern to substantially eliminate said transition,
• e. etching an aperture in said thick layer of silicon dioxide to communicate with said diaphragm,
• f. forming a piezoresistor element in said wafer within said aperture in cooperation with said contact pattern, and
• g. metalizing a peripheral area of said thick layer to provide a relatively smooth bonding surface for said diaphragm.

A method of fabricating a transducer, comprising the steps of:

• a. growing a first layer of silicon dioxide on a first surface of a silicon wafer,
• b. forming a contact pattern on said surface using a silicon dioxide masking technique,
• c. depositing impurities within said contact pattern to form ohmic contacts,
• d. growing a thicker layer of silicon dioxide over said first layer and said contact pattern,
• e. etching said first and thick layer of silicon dioxide to form an opening therein,
• f. depositing at least one piezoresistor element within said opening on said silicon wafer,
• g. forming terminals about said contact pattern by a metalization technique, said terminals coupled to said element,
• h. depositing a metal ring about the periphery of said thick layer of silicon dioxide with said terminals encircled by U-shaped apertures in said ring,
• i. glass bonding said diaphragm to an annular housing with said bond formed between said metal ring a surface of said housing.