New developments in thermal wave microscopy

Near field scanning thermal wave microscopes which offer lateral resolution in the submicron range are either based on the detection of the thermoelas tic response or a thermal probe is used. Recently we have shown that the sc anning thermo-elastic microscope provides a means to measure simultaneously topological and thermal structures. In this report the signal generation p rocess is investigated in detail for the microscope applied to an electrica lly heated semiconductor devices such as an in-plane-gate transistor and a non-conduction line on a mesa. Additional contributions to the signal consi dered comprise electrostatic effects, heating of the tip and piezoelectric deformations. Introducing a calibration method a quantitative information o f the local thermo-elastic expansion of the surface is obtained from which the temperature distribution is deduced by a finite element calculation. Co mbined optical and electrical heating provides a means to imagine also buri ed structures such as insulating lines produced by focused ion beams.