A study on the fabrication of an RTD (resistance temperature detector) by using Pt thin film

Pt thin film was deposited on alumina substrate by using DC sputter and the serpentine pattern was formed by photolithography to fabricate the resista nce temperature detector (RTD). The Pt film was thermally treated and the s urface structure of the film and its effect on the electrical resistance we re studied. The sheet resistance of the film depends on the thickness and t hermal treatment. The developing and etching conditions for serpentine patt erning of the film were investigated and various RTD samples were prepared. All of the fabricated RTD's show a good linear variation of resistance wit h the temperature. The temperature coefficient of resistance (TCR) values o f RTD's increased with decreasing film thickness, narrowing pattern line wi dth, and increasing annealing temperature. The highest TCR value was obtain ed from RTD with 1 mm line width thermally treated at 700 degreesC and was 3.53x10(3) ppm/degreesC.