A piezo-thermal probe for thermomechanical analysis

Abstract

Thermomechanical analysis (TMA) is widely used to characterize materials and determine transition temperatures and thermal expansion coefficients. Atomic-force microscopy (AFM) microcantilevers have been used for TMA. We have developed a micromachined probe that includes two embedded sensors: one for measuring the mechanical movement of the probe (deflection) and another for providing localized heating. The new probe reduces costs and complexity and allow for portability thereby eliminating the need for an AFM. The sensitivity of the deflection element (( R/R)/deflection) is 0.1 ppm/nm and its gauge factor is 3.24. The melting temperature of naphthalene is measured near 78.5 • C.

Hot-spot detection and calibration of a scanning thermal probe with a noise thermometry gold wire sample

“…The scanning thermal probe is micromachined in a four-mask fabrication process. [17][18][19] The cantilever is a stacked structure of Si and SiO 2 layers 300 lm long, 200 lm wide, and 2 lm thick, as shown in the scanning electron microscopy (SEM) image Figure 1(a). The two sensing elements are 10-nm-thick gold films.…”

“…For this study, we used a micro-machined scanning thermal probe [17][18][19] measuring deflection, and another for measuring localized heating. In a typical application, the temperature profile of the sample is obtained by monitoring the sensor resistance during a probe scan.…”

Tip-based chemical vapor deposition with a scanning nano-heater

“…The nano-heater is calibrated using a thermocouple. 15 A custom made scanning system, illustrated in Fig. 1(a), resides inside a glass chamber.…”

“…The tip is heated resistively and the nano-heaters are designed so that most of the heating occurs at the contact area. [15][16][17] The nano-heater includes a metal resistor that acts as a heating element, made of 10 nm Ti and 100 nm Ir film, with nominal resistance of 8.15 X, deposited on a Si and SiO 2 cantilever. The fabrication of the nano-heater is described in prior publications.…”

“…The fabrication of the nano-heater is described in prior publications. [15][16][17] The nano-heater comprises of a 20 lm tall tip with a <500 nm tip diameter and a passivation layer covering the cantilever and the tip made of a 100 nm Si 3 N 4 layer. The device is annealed at 900 C for 2 h. It is operated at 288 mW by passing current through the resistor, which corresponds to a temperature of approximately 298.…”