High sensitivity acoustic transducers with thin p+ membranes and gold back-plate
1999; Elsevier BV; Volume: 78; Issue: 2-3 Linguagem: Inglês
10.1016/s0924-4247(99)00242-3
ISSN1873-3069
AutoresA.E. Kabir, Rashid Bashir, Jonathan Bernstein, Jessica De Santis, Royce Mathews, J.O O'Boyle, Chris Bracken,
Tópico(s)Innovative Energy Harvesting Technologies
ResumoHigh sensitivity acoustic transducers (microphones) have been fabricated on 5″ wafers in a production environment and the experimental results are presented. One of the main advantage of this microphone design is that it can be fabricated on a single wafer eliminating the need for the multiple wafers and subsequent wafers bonding steps as in conventional designs. The devices use thin (∼3 μm) p+ silicon membranes as the active movable element and a thick perforated plated gold back plate. The p+ membranes are fabricated using an optimized boron solid source diffusion at 1150°C. Ethylene–Diamine–Pyro-Catecol (EDP) etching at 100°C was performed from the backside of double-sided polished wafers to release the thin silicon membranes. The zero-bias capacitance with the air gap was 2.2 pF and it increased to 2.4 pF at 9 V. The frequency response was measured and the measured sensitivity of 5.28 mV/Pa at 5 V and 10.77 mV/Pa at 9 V at 1 kHz are among the highest reported in literature for micro-machined acoustic transducers.
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