Combinatorial Characterization of Chemiresistive Films Using Microhotplates

When producing chemical sensors, especially in thin film form, there are often a large variety of processing variables that are believed to impact the ultimate performance of the materials. It is thus advantageous to find methods for simultaneous, high-throughput characterization of many process variables. Here, we report on a method for using MEMS-based microhotplates to create and characterize arrays of chemiresistive SnO thin films. The microhotplates are used both to control the thermal process variables at each element of the array during film growth by CVD as well as subsequently to operate the sensors. Example chemiresistive properties of the films at 200°C were characterized during exposure to CH OH and NO . Through the use of a fractional factorial experiment design, the effects of 4 different process variables (growth temperature, thickness, presence of a dopant and use of rapidly pulsed heating during growth) were reliably determined using only 8 films and the associated statistical modeling of the results .