A detection system and a method of making a detection system

摘要

A bolometric detection system for detecting electromagnetic radiation with frequencies from 300GHz to 1THz is disclosed with a narrow or wide band antenna 6 directly connected to a suspended metal film thermistor 5 fabricated on a thin (3 - 5μm) self-supporting dielectric membrane 3. The thermistor 5 is suspended above the membrane 3, which is fabricated with a planarised process to minimise the thermistor dimensions scattering. The detection system includes a reflecting cavity 9 which is a λ/4 THz mirror. The depth dR of the THz mirror 9 can be controlled solely by the thickness of the silicon wafer 7. The thickness can alternatively be controlled by providing a separate silicon wafer 7 with a metallised groove 9 that is bonded by a low temperature bonding process to the detecting silicon wafer 1. The system is optimised for a thermistor resistance of about 800Ω, which is slightly more than twice the impedance of free space (Z0 = 377Ω).