A CMUT or other semiconductor-based transducer is stacked with a piezoelectric transducer (PZT). The CMUT is sufficiently thin to avoid or limit interference with sound propagation through the CMUT from or to the PZT or crosstalk between transmitter elements. The PZT/CMUT layered structure is used as a matrix array, such as an array with a multi-dimensional arrangement of elements. The CMUT array is formed and thinned using semiconductor processing. The PZT transmits acoustic energy through the thin CMUT. The CMUT receives responsive echoes. Using integrated electronics in the thin wafer of the CMUT limits interconnection problems for the matrix receive array.