{'fraction_non_alphanumeric': 0.010976948408342482, 'fraction_numerical': 0.0010976948408342481, 'mean_word_length': 5.039735099337748, '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}}
Focused ion-beam vacuum lithography of InP with an ultrathin native oxide resist

A vacuum lithographic process for InP-based semiconductors has been developed. It employs a focused Ga ion beam to write patterns on an ultrathin native oxide resist thermally grown on the surface of InP. The pattern is transferred into the substrate by Cl2 etching. Depending on its thickness and composition the oxide is removed by either thermal desorption or by low energy Ar ion bombardment. This lithographic process is compatible with molecular beam epitaxy and has been used to create high quality GaInAsfInP heterostructures on patterned InP substrates. The details of this process are reported with an emphasis on the formation and removal of the oxide resist. Its composition and thickness as a function of oxidation temperature are examined using Auger analysis and a novel in-situ measurement technique respectively.