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.