{'fraction_non_alphanumeric': 0.035487959442332066, 'fraction_numerical': 0.015209125475285171, 'mean_word_length': 4.448275862068965, '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}}
Low-Temperature Bonding of GaN on Si Using a Nonalloyed Metal Ohmic Contact Layer for GaN-Based Heterogeneous Devices

A low-temperature integration process for GaN-based heterogeneous devices was demonstrated by low-temperature bonding with Cr/Au thin films. Nonalloyed Cr/Au ohmic contacts on n-type GaN were obtained by surface treatment with low-energy fast atom beams of Ar for 15 s prior to metal deposition on n-type GaN. The as-deposited Cr/Au (50/250 nm) contacts showed a smooth surface with a root-mean-square roughness of 1.8 nm. Au-Au surface-activated bonding was carried out at 150°C in ambient air after surface activation by an Ar radio-frequency plasma. The GaN/Si samples bonded at a low temperature were so strong that bulk fracture was observed after the tensile test.