Yoon, YS Kim, JH Polla, DL Shin, YH 2024-01-21T16:16:56Z 2024-01-21T16:16:56Z 2021-09-03 1998-12 0021-4922 https://pubs.kist.re.kr/handle/201004/142701 This paper analyses the problems posed by the interface structure during chemical etching by Hydro-fluoric (HF) acid for creating air gaps in microelectromechanical system (MEMS) devices using PZT(53/47) films and surface micromachining techniques. In order to investigate the influence of interface structure on the HF chemical etching process. Pt/PZT/Pt/Ti/TiO2/polysilicon/Si3N4/PSG/Si (Samples A and C) and Pt/PZT/RuO2/Ru/Si3N4/PSG/Si (Sample B) structures were fabricated. These structures are selected for a microcantilever beam and/or an uncooled TR detectors fabricated; with PZT piezoelectric/pyroelectric films based on the surface micromachining technique. Both need etching for the removal of phosphor silicate glass (PSG) to create an air gap. If the devices had a poor interface structure, they would fail during the HF chemical etching process because the poor interface structure would act as a kind of penetration path for etching acid leading to unwanted etching. Therefore, it is very important to investigate the interface structure to fabricate efficient MEMS devices. In this study two different solutions have been suggested to improve the interface structure. The first is post thermal annealing at 900 degrees C for 30 min. after deposition of polycrystalline silicon for sample A. Secondly, a RuO2/Ru hybrid electrode was deposited on Si3N4 directly instead of on the Pt/Ti/TiO2/Polysilicon electrode, which has Pt/PZT/RuO2/Ru/Si3N4/PSG/Si as the device structure. These two solutions suggest that a dense interface structure increases enhances of success of the chemical etching process of MEMS devices fabricated using PZT films and surface micromachining techniques. English JAPAN SOC APPLIED PHYSICS FILMS Influence of interface structure on chemical etching process for air gap of microelectromechanical system based on surface micromachining Article 10.1143/JJAP.37.7129 1 JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, v.37, no.12B, pp.7129 - 7133 JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 37 12B 7129 7133 scie scopus 000078699200093 2-s2.0-0000410939 Physics, Applied Physics Article; Proceedings Paper FILMS MEMS interface PZT chemical etching process