AVS 47th International Symposium
    Plasma Science and Technology Friday Sessions
       Session PS-FrM

Paper PS-FrM6
CVD BST (Ba@sub x@Sr@sub 1-x@TiO@sub 3@) Etching Characteristics in Inductively Coupled Ar/Cl@sub 2@ Plasma

Friday, October 6, 2000, 10:00 am, Room 310

Session: Dielectrics II
Presenter: I.-Y. Kwon, Hyundai Electronics Industries Co. Ltd., Korea
Authors: I.-Y. Kwon, Hyundai Electronics Industries Co. Ltd., Korea
H.-S. Shin, Hyundai Electronics Industries Co. Ltd., Korea
J.W. Kim, Hyundai Electronics Industries Co. Ltd., Korea
Correspondent: Click to Email
We investigated the etching characteristics of CVD BST film with Ar/Cl@sub 2@ gas chemistry in ICP reactor. The changes of BST etch rate with various etching parameters such as gas mixing ratio, source power, bias power, pressure, and total flow rate were systematically examined. And, electron density, electron temperature, ion density, and plasma potential of Ar/Cl@sub 2@ plasma were measured with L/P, and also representative ions and neutrals in the plasma were analyzed by OES, RGA, and SIMS. XPS was employed for the surface analysis of BST film. Upon varying Ar/Cl@sub 2@ gas mixing ratio, the maximum BST etch rate was observed at 40% Cl@sub 2@. It was generally regarded that Cl@sub 2@ gas assisted BST etching chemically by the formation of some chlorides on the BST surface. XPS results showed that peak shifts including Ti, Ba, Cl were induced by the formation of chlorides. However, Ti remaining on the BST surface was decreased with increasing Cl@sub 2@ gas until 40%, and then saturated above 40% Cl@sub 2@. And, the changes of Ti, Ba, Sr and Cl ions and neutrals with Ar/Cl@sub 2@ ratio showed same saturation tendency by OES and QMS analysis. Therefore, it is estimated that the chemical etch portion of Cl@sub 2@ gas in BST etching is saturated at 40% Cl@sub 2@. On the other hand, ion saturation current decreased dramatically as the Cl@sub 2@ gas addition to Ar gas, and relative DC-bias and ion energy in plasma decreased with increasing Cl@sub 2@ gas above 40%. Therefore, it is also estimated that the physical sputtering with Ar/Cl@sub 2@ gas ratio rapidly decreases over 40% Cl@sub 2@ addition. Based on these results, it could be thought that the BST etch rate increases by chemical etch portion of Cl@sub 2@ gas under 40% Cl@sub 2@, and then is determined by physical sputtering above 40% Cl@sub 2@ due to the saturation of chemical etch portion. So, we propose chemically-assisted physical sputtering as a etch mechanism of BST film in Ar/Cl@sub 2@ plasma.