Submicrosecond range surface heating and temperature measurement for efficient sensor reactivation

A method for submicrosecond heating of sensor surfaces and simultaneous det ection of the surface temperature was developed enabling accurate and fast reactivation of a semiconductor based oxygen sensor. High power electrical pulses with current densities of more than 10(7) A/cm(2) were applied to th e 60-nm-thick Pt layer of a chemical semiconductor sensor structure resulti ng in surface temperatures as high as 700 K maintained in the nanosecond to microsecond range. Temperature measurement was carried out using the tempe rature dependent electrical resistance of the Pt film. Electrical power pul ses of defined shape allowed accurate control of the surface temperature wi th ns time resolution. The high reactivation surface temperatures required high current densities, eventually leading to fatal destruction of the sens or structure. Comparative numerical simulations of the thermal impact as we ll as photo thermal and scanning force microscopy measurements were perform ed to optimize the heating process and to investigate the destruction mecha nism. (C) 2001 Elsevier Science B.V. All rights reserved.