An antenna-coupled bolometer is a viable approach to detect terahertz (THz) waves. For resistive bolometers, the important criterion is the temperature coefficient resistance (TCR) of thermistor material, since it is directly proportional to responsivity (R_v) and inversely proportional to the noise equivalent power (NEP). Especially, the device performances of metallic bolometer directly gets benefit from the improved TCR. The TCR of thin and narrow wires is affected by the presence of defects or grain boundaries, and can be increased by annealing. Therefore, this time we study the effect of Joule heating caused by the large current through the wire. The fabricated titanium (Ti) wire structure and its cross-section are shown in Fig. 1 (a & b). Ti has been selected as a possible candidate for thermistor material due to its large resistivity and small thermal conductance. Ti wire was formed by patterning of electron-beam (EB) evaporated Ti thin film using laser lithography. After that the deep cavity for thermal isolation was formed by CHF3 RIE and SF6 plasma etching.
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