AVS 47th International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS-TuP

Paper PS-TuP4
The Boron Effects on YMnO@sub 3@ Thin Films Etching in High Density Ar/Cl@sub 2@/BCl@sub 3@ Plasma

Tuesday, October 3, 2000, 5:30 pm, Room Exhibit Hall C & D

Session: Poster Session
Presenter: B.J. Min, Chungang University, Korea
Authors: B.J. Min, Chungang University, Korea
Y.T. Kim, KIST, Korea
C.-I. Kim, Chungang University, Korea
Correspondent: Click to Email
Ferroelectric materials, such as Pb(Zr,Ti)O@sub 3@ (PZT), SrBi@sub 2@Ta@sub 2@O@sub 9@ (SBT), (Ba,Sr)TiO@sub 3@ (BST), YMnO@sub 3@ have attracted much attention for use in nonvolatile memories. In particular, YMnO@sub 3@ thin films are excellent materials for high integrated ferroelectric random access memory (FRAM) with metal-ferroelectric-silicon field effect transistor (MFSFET) structure. Although etching processes for YMnO@sub 3@ thin films must be developed to fabricate MFSFET type FRAM, etching of YMnO@sub 3@ have not been reported. Thus, we studied the etching properties of YMnO@sub 3@ thin films using high density plasma. In this study, YMnO@sub 3@ thin films were etched with Ar/Cl@sub 2@/BCl@sub 3@ gas chemistries in inductively coupled plasma (ICP). Photoresist (PR) and SiO@sub 2@ were used as mask materials. Etching properties of YMnO@sub 3@ were measured according to the various etching parameters such as rf power, dc bias voltage, chamber pressure and gas mixing ratio. The trends in the effect on etch rate and selectivity to mask materials for BCl@sub 3@ ratio to Ar/Cl@sub 2@ have been determined. YMnO@sub 3@ was dominantly etched by Ar ion bombardment. Selectivity to PR and SiO@sub 2@ increased as decreasing mole fraction of Ar gas. Additive BCl@sub 3@ enhanced relative etch rate, selectivity and profile. Chemical reaction and residue of etched surface was investigated with x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). As mole fraction of BCl@sub 3@ varied, boron effects with respect to residue were investigated by etched profile of SEM (scanning electron microscopy) image. In order to analyze the effect of radical density of Cl and ion current density in plasma of various gas chemistries, optical emission spectroscopy (OES) and single Langmuir probe were utilized. Change of stoichiometry on the etched surface is discussed by comparing with OES analysis.