A silicon-silicon nitride membrane fabrication process for smart thermal sensors

• Published in: Sensors and actuators. A, Physical Physical, 1994-04, Vol.42 (1), p.666-671
• Main Authors: Sarro, P.M., van Herwaarden, A.W., van der Vlist, W.
• Format: Article
• Language: English
• Subjects: Calorimetry; Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); Instrumentation for fluid dynamics; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Physics; Thermal instruments, apparatus and techniques; Vacuum apparatus and techniques; Vacuum gauges
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/0924-4247(94)80072-3

A new structure consisting of a silicon membrane suspended in a nitride membrane has been realized. This structure combines the advantages of the high thermal isolation of nitride membranes and the use of bipolar devices as sensing elements. The nitride membrane and the silicon membrane are fabricated within a single etch step. The process and its options are described by a design that includes several mono-Si thermopiles in a 2.5 μm thick silicon membrane and poly-Si thermopiles resting on a 0.3–0.8 μm thick oxide/nitride membrane. In all cases diodes, transistors and heating resistors are integrated as well. To prove the versatility of this process, as well as to,indicate which thermal configuration is more suitable for a specific application, a number of sensors realized with.this process will be briefly described.