In this work we present an array of piezoelectric micromachined ultrasound transducer (PMUT’s) based on AlScN piezoelectric layer, monolithically integrated on top of a 130 nm CMOS circuit. The array along with the analog-front-end circuit has been configured to work as a linear phased array. Experiments carried out have demonstrated the homogeneous PMUT’s behavior, showing a small dispersion in terms of frequency, bandwidth, and sensitivity. The feasibility of easily performing a transmission beam steering and focusing has been proven. In particular, the beam directivity has been characterized in terms of the width of the main lobe. The integrated CMOS analog-front-end allows the reduction of parasitic elements and noise, improving the signal to noise ratio (SNR). As a proof of concept, a B-mode image, with a 16 dB dynamic range, using a single AlScN PMUT-on-CMOS channel as a receiver has been obtained.