Microcantilever with integrated solid-state heater, conductive tip, and Schottky diode

This paper reports a heated atomic force microscope cantilever having a Schottky diode fabricated near the cantilever free end. The forward bias and reverse bias operation of this cantilever offer different current–voltage characteristics, such that the cantilever heating and temperature sensing capabilities are different in forward bias versus reverse bias operation. When 43 V is applied to the cantilever, the cantilever temperature is 677 °C in the forward bias and 786 °C in reverse bias. Thermal runaway for the device occurs at 445 °C, corresponding to forward and reverse bias resistances of 1.2 kΩ and 2.0 kΩ. Below the thermal runaway point, the cantilever temperature coefficient of resistance (TCR) is 943 ppm/°C in the forward bias and 2996 ppm/°C in reverse bias. We characterize cantilever thermomechanical bending, which is a function of bias direction, applied voltage, and actuation frequency. The diode junction at the cantilever free end grants an additional degree of electro-thermal and thermomechanical control compared to other types of heated cantilevers.