AVS 51st International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS-MoP

Paper PS-MoP17
Dry Etching of (Pb,Sr)TiO@sub 3@ Thin Films Using Inductively Coupled Plasma

Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: C.I. Kim, Chungang University, Korea
Authors: C.I. Kim, Chungang University, Korea
K.T. Kim, Chungang University, Korea
G.H. Kim, Chungang University, Korea
T.H. Kim, YeoJoo Institute of Technology, Korea
C.I. Lee, Ansan College of Technology, Korea
Correspondent: Click to Email
Recently, ferroelectric thin films have received great attention for the application to high density memory devices. Among the various ferroelectric films, the BST thin film was noticed as the most promising material due to its high dielectric constant and paraelectricity at normal operating temperature. Although BST possesses a satisfactorily high dielectric constant, it was known that a post heat treatment at a high temperature was essential to obtain good electrical property. The heat treatment at high temperature can cause deleterious effects on an electrode, barrier metal, and contact plug. Strontium titanate (SrTiO@sub 3@) is one of the few titanates which is cubic at room temperature. But, the dielectric constant is lower than BST. The addition of lead into strontium titanate makes its dielectric constant(1377) higher and the temperature of crystallization lower. Therefore, (Pb,Sr)TiO@sub 3@ (PST) thin film can be a promising material due to its high dielectric constant and paraelectricity at normal operating temperature. However, there is no report on the characteristics and mechanism of PST thin films during etching process. In this study, inductively coupled plasma etching system was used for etching PST because of its high plasma density, low process pressure and easy control bias power. The etching characteristics of PST thin films were investigated in terms of etch rates and selectivity as a function of gas mixing ratio, rf power, dc bias voltage and chamber pressure. The BCl@sub 3@/Cl@sub 2@/Ar plasmas were characterized by optical emission spectroscopy (OES), quadruple mass spectrometry (QMS) and Langmuir probe analysis. The chemical states on the etched surface were investigated with x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). Scanning electron microscopy (SEM) was used to investigate the etching profile.