{'fraction_non_alphanumeric': 0.0175, 'fraction_numerical': 0.0, 'mean_word_length': 6.088495575221239, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Increased Output-Pressure PMUTs with a Sloped Profile Fabricated via Surface Micromachining

This study demonstrates a new surface micromachining process capable of forming AIN piezoelectric micromachined ultrasonic transducers (PMUTs) having a sloped profile. Similar to earlier curved PMUT structures, the sloped profile increases the electromechanical coupling of the piezoelectric layer, leading to a three-fold enhancement in transmission amplitude. Unlike earlier curved PMUTs which were fabricated using complicated etching processes, the process demonstrated here is a simple surface micromachining process that is compatible with mass production processes used for industrial PMUT manufacture. Moreover, the quality factor can be improved by sloped-anchor of diaphragm with less anchor-loss.