Optimized membrane configuration improves CMUT performance

The performance of a capacitive micromachined ultrasonic transducer (CMUT) was improved by optimizing its membrane configuration. CMUTs with three different membrane configurations: square, rectangular and tent, were designed and fabricated using a process based on the wafer-bonding technique. Paired tests showed that improved transmission (TX) and reception (RX) efficiencies were achieved by using tent or rectangular membranes instead of square membranes. The improvements were 46% and 44% in TX and 43% and 65% in RX, respectively.