Dry and wet etch processes for NiMnSb, LaCaMnO 3 and related materials

J. Hong, J. J. Wang, E. S. Lambers, J. A. Caballero, J. R. Childress, S. J. Pearton, K. H. Dahmen, S. Von Molnar, F. J. Cadieu, F. Sharifi

Research output: Chapter in Book/Report/Conference proceedingConference contribution


A variety of plasma etching chemistries were examined for patterning NiMnSb Heusler thin films and associated Al 2O 3 barrier layers. Chemistries based on SF 6 and Cl 2 were all found to provide faster etch rates than pure Ar sputtering. In all cases the etch rates were strongly dependent on both the ion flux and ion energy. Selectivities of ≥20 for NiMnSb over Al 2O 3 were obtained in SF 6-based discharges, while selectivities ≤5 were typical in Cl 2 and CH 4/H 2 plasma chemistries. Wet etch solutions of HF/H 2O and HNO 3/H 2SO 4/H 2O were found to provide reaction-limited etching of NiMnSb that was either non-selective or selective, respectively, to Al 2O 3. In addition we have developed dry etch processes based on Cl 2/Ar at high ion densities for patterning of LaCaMnO 3 (and SmCo permanent magnet biasing films) for magnetic sensor devices. Highly anisotropic features are produced in both materials, with smooth surface morphologies. In all cases, SiO 2 or other dielectric materials must be used for masking since photoresist does not retain its geometrical integrity upon exposure to the high ion density plasma.

Original languageEnglish
Title of host publicationMaterials Research Society Symposium - Proceedings
EditorsS.J. Pearton, R.J. Shul, E. Wolfgang, F. Ren, S. Tenconi
Number of pages6
Publication statusPublished - 1997
Externally publishedYes
EventProceedings of the 1997 Fall MRS Symposium - Boston, MA, USA
Duration: 1 Dec 19974 Dec 1997


OtherProceedings of the 1997 Fall MRS Symposium
CityBoston, MA, USA


ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

Cite this

Hong, J., Wang, J. J., Lambers, E. S., Caballero, J. A., Childress, J. R., Pearton, S. J., Dahmen, K. H., Von Molnar, S., Cadieu, F. J., & Sharifi, F. (1997). Dry and wet etch processes for NiMnSb, LaCaMnO 3 and related materials In S. J. Pearton, R. J. Shul, E. Wolfgang, F. Ren, & S. Tenconi (Eds.), Materials Research Society Symposium - Proceedings (Vol. 494, pp. 3-8). MRS.