AVS 45th International Symposium
    Magnetic Interfaces and Nanostructures Technical Group Thursday Sessions
       Session MI-ThP

Paper MI-ThP1
Comparison of Cl@sub2@ and F@sub2@ Based Chemistries for the Inductively Coupled Plasma Etching of NiMnSb Thin Films

Thursday, November 5, 1998, 5:30 pm, Room Hall A

Session: Magnetic Interfaces and Nanostructures Poster Session
Presenter: J. Hong, University of Florida, Gainesville
Authors: J. Hong, University of Florida, Gainesville
J.A. Caballero, University of Florida, Gainesville
E.S. Lambers, University of Florida, Gainesville
J.R. Childress, University of Florida, Gainesville
S.J. Pearton, University of Florida, Gainesville
Correspondent: Click to Email
Plasma etching chemistries based on BCl@sub3@/Ar, BCl@sub3@/H@sub2@ and NF@sub3@/Ar were studies for patterning NiMnSb Heusler Alloys thin films and associated Al@sub2@O@sub3@ barrier layers under Inductively Coupled Plasma. Using BCl@sub3@/Ar discharges, high etch rates (@>=@1µm) were achieved either at high source power (1000W) or high dc self bias (-300V) and etch rates showed a strong dependence upon source power, ion energy and gas composition. Hydrogen addition to the BCl@sub3@ created new species (HCl) in the plasma, leading to the fast etching for NiMnSb, in contrast to the situation of Ar addition. Selectivities of @>=@8 for NiMnSb over Al@sub2@O@sub3@ were obtained in BCl@sub3@-based discharges. On the other hand, NF@sub3@/Ar discharges provided a narrow process window for the etching of NiMnSb and etch rates of NiMnSb were much lower compared to BCl@sub3@. The surface of NiMnSb etched with NF@sub3@/Ar was smoother with RMS surface roughness of 1.4nm measured by Atomic Force Microscopy than the surface produced with BCl@sub3@/Ar. In terms of near surface chemistry, etched surface with NF@sub3@/Ar revealed Mn-enriched, indicating the existence of involatile Mn etch products, whereas Mn-deficiency at the near surface was obtained with BCl@sub3@/Ar.