Suspended epitaxial YBaCuO bolometers on silicon and SIMOX substrates

Suspended epitaxial YBaCuO bolometers were successfully fabricated by two silicon micromachining techniques. The first one used the RIE (Reactive Ion Etching) of Si substrates and the second one the etching of the SiO/sub 2/ layer in SIMOX (Separated by IMplanted OXygen) substrates. Thermal conductances and time constants of different suspended bridges fabricated by RIE were measured as functions of length and width. The influence of the materials constituting the membrane was discussed by comparing a "RIE bridge" to a similar "SIMOX bridge". All measurements were consistent with calculations from thermal model. Experimental results and model lead to the optimization of a 100/spl times/100 /spl mu/m/sup 2/ IR detector. Its detectivity D*, measured at 85 K under irradiation from a blackbody, was 2.5 10/sup 9/ cm/spl radic/(Hz)/W, with a time constant of 564 /spl mu/s. These performances are among the best reported for YBaCuO bolometers.