1. Field
The exemplary embodiments relate to capacitive micromachined ultrasonic transducers using a plurality of conductive material layers defined by trenches as bottom electrodes and methods of fabricating the same.
2. Description of the Related Art
A micromachined ultrasonic transducer (MUT) is a device capable of converting electric signals into ultrasonic signals or converting ultrasonic signals into electric signals. Such MUTs may be categorized into piezoelectric micromachined ultrasonic transducers (PMUT), capacitive micromachined ultrasonic transducers (CMUT), and magnetic micromachined ultrasonic transducers (MMUT) according to a conversion mechanism.
A conventional CMUT supplies electricity to a top electrode by using a through via formed in a low-resistance wafer. During formation of the through via, a corner of a through via hole may not be completely coated by a passivation layer, and a metal layer for the through via may contact the low-resistance wafer, and thus, the through via and the low-resistance wafer may be short-circuited. Furthermore, a masking process for forming the through via is required.