Reduction of surface roughness of a silicon chip for advanced nanocalorimetry

A silicon chip designed to combine nanocalorimetry with scanning probe microscopy (SPM) has been realized. For the SPM application, as an additional requirement, a very low surface roughness of the scanned area becomes imperative. Several steps in the basic process flow are examined by atomic force microscopy (AFM) and modified in order to meet the surface roughness demands of a root mean square (rms) roughness below 1 nm as well as a negligible nanoparticle count. In particular, spin-on benzocyclobutene (BCB) layers are demonstrated to give a versatile means of achieving a surface that is smooth enough for calorimetry of nanometer-thin films while simultaneously allowing the investigation of nanometer scale morphological features by means of SPM.