AVS 45th International Symposium
    Electronic Materials and Processing Division Tuesday Sessions
       Session EM+SE-TuM

Paper EM+SE-TuM9
Critical Development Issues for Deep (10 to 100 µm) Etching of SiC

Tuesday, November 3, 1998, 11:00 am, Room 316

Session: Critical Issues in Widebandgap Semiconductors
Presenter: J.B. Casady, Northrop Grumman
Authors: D.C. Sheridan, Auburn University
J.B. Casady, Northrop Grumman
C.E. Ellis, Auburn University
R.R. Siergiej, Northrop Grumman
J.D. Cressler, Auburn University
W.E. Urban, Northrop Grumman
W.F. Valek, Northrop Grumman
H. Buhay, Northrop Grumman
Correspondent: Click to Email
Silicon carbide is a wide bandgap (3.2 eV for the 4H polytype) semiconductor gaining popularity in applications requiring high-power, high-frequency, and high-temperature performance@footnote 1@. Material quality improved significantly since the first commercial release of SiC substrates in 1991. Numerous SiC semiconductor devices have been developed, such as thyristors, diodes, JFETs, MESFETs, and static induction transistors. Because of its high bond strength, the etching of SiC has been quite difficult, performed almost exclusively using dry etching techniques. Most techniques have utilized fluorinated gas chemistries in reactive ion etch (RIE), electrocyclotron resonance (ECR) etch, or inductively coupled plasma (ICP) etch systems. Residue free etches have been developed with etch rates from 5 nm/minute up to 350 nm/minute@footnote 2,3@. For very deep etching of SiC, up to 75 µm, which would be required for selected applications, no suitable process has been reported on. The ideal process would optimize a combination of fast etch rate, good mask selectivity, and reproducibility. In this work, we compare five SiC etches used in commercial RIE systems with regard to the above criteria. The SiC etches examined are all residue-free, and posses etch rates ranging from 8 nm/minute up to 160 nm/minute. The etches utilize one or more of the following fluorinated gases: NF@sub 3@, SF@sub 6@, CHF@sub 3@, or CF@sub 4@. A more detailed characterization of the etch recipes will be given in the full paper, and partial details have been reported elsewhere@footnote 4,5,6@. Several inorganic and organic mask materials will also be evaluated. Each mask material is characterized and tabulated in terms of etch rate, selectivity, and residue-formation for each of the SiC etches. @FootnoteText@ @footnote 1@ J.B. Casady and R.W. Johnson, Solid-St. Elect., Vol. 39, No. 10, p. 1409, 1996. @footnote 2@ P.H. Yih, V. Saxena, and A.J. Steckl, Phys. Stat. Sol. (b) Vol. 202, p. 605, 1997. @footnote 3@ G. McDaniel, J.W. Lee, E.S. Lambers, S.J. Pearton, P.H. Holloway, F. Ren, J.M. Grow, M. Bhaskaran, and R.G. Wilson, J. Vac. Sci. Technol. A, Vol. 15 @footnote 4@ J.B. Casady, E.D. Luckowski, M. Bozack, D. Sheridan, R.W. Johnson, and J.R. Williams, J. Electrochem. Soc., Vol. 143, No. 5, p. 1750, 1996. @footnote 5@ P.H. Yih and A.J. Steckl, J. Electrochem. Soc., Vol. 140, p. 1813, 1993. @footnote 6@ J.B. Casady, S.S. Mani, R.R. Siergiej, W. Urban, V. Balakrishna, P.A. Sanger, and C.D. Brandt, J. Electrochem. Soc., Vol. 145, No. 4, p. L58, 1998.