Optimization of piezoelectric MEMS process on Sr and La co-doped PZT thin films

Autor: M. Kathiresan, Jain Jose, E. Varadarajan, R. Ramesh, V. Natarajan, M. K. Jayaraj, T. Santhanakrishnan
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Journal of Advanced Dielectrics, Vol 10, Iss 4, Pp 2050010-1-2050010-7 (2020)
Druh dokumentu: article
ISSN: 2010-135X
2010-1368
2010135X
DOI: 10.1142/S2010135X20500101
Popis: Doped lead–zirconate–titanate (PZT) thin films are preferred for the development of micro–electro–mechanical systems (MEMS)-based acoustic sensors because of their inherent higher dielectric and piezoelectric coefficients. Patterning process is used to develop such MEMS devices which is highly complex even for undoped PZT thin films; therefore, the problem is further cumbersome for doped PZT thin films due to the presence of added dopant elements and their associated chemistry. This paper presents patterning of strontium (Sr) and lanthanum (La) co-doped PZT thin film (PSLZT) deposited on platinized silicon substrate using wet and dry etching processes for fabricating a diaphragm structure with thickness of 15–25μm and diameter of 1.4–2mm, suitable for acoustic sensing applications. The effects of various etching conditions have been studied and the results are reported. It is found that the dry etching is the most suited process for realizing the piezoelectric MEMS structure due to its higher etching resolution. An appreciable etching rate of 260–270nm/min with smooth vertical sidewalls is achieved. The silicon diaphragm with patterned PSLZT thin film is found to retain more than 80% of its dielectric and piezoelectric coefficients and has a resonance of 1.43MHz.
Databáze: Directory of Open Access Journals