AVS 47th International Symposium
    Photonics Tuesday Sessions
       Session PH-TuA

Paper PH-TuA6
Comparison of Dry and Wet Etch Processes for SiO@sub 2@/TiO@sub 2@ Distributed Bragg Reflectors for Vertical Cavity Surface Emitting Lasers

Tuesday, October 3, 2000, 3:40 pm, Room 310

Session: Challenges in Photonics Materials and Device Processing
Presenter: G. Dang, University of Florida
Authors: G. Dang, University of Florida
H. Cho, University of Florida
K.P. Lee, University of Florida
S.J. Pearton, University of Florida
S.N.G. Chu, Bell Labs, Lucent Technologies
J. Lapata, Bell Labs, Lucent Technologies
W.S. Hobson, Bell Labs, Lucent Technologies
F. Ren, University of Florida
Correspondent: Click to Email
Vertical-Cavity Surface Emitting Lasers (VCSELs) have generated much interest in the photonic devices field. They show tremendous promise for commercial applications involving optical fiber wave-guiding and optoelectronic integrated circuits. The semiconductor-based distributed Bragg reflector (DBR) and dielectric mirror are commonly used in VCSELs. We demonstrated a dry etch process of fabricating SiO@sub 2@/TiO@sub 2@ distributed Bragg reflector for 850 and 980 nm vertical cavity surface emitting lasers. The etchings was conducted with an inductively coupled plasma system. Both SF@sub 6@/Ar and Cl@sub 2@/Ar based etching chemistries were investigated. Very slow etch rates were obtained for TiO@sub 2@ by using Cl@sub 2@/Ar chemistry due to the low volatility of etch products, TiCl@sub x@. Using SF@sub 6@/Ar based chemistry, similar etch rates of TiO@sub 2@ and SiO@sub 2@ were obtained which is desired for alternating SiO@sub 2@/TiO@sub 2@ layers etching. An average etch rate of 1200 Å/min was achieved at ICP and rf power of 500 and 245W, respectively. Wet chemical etch processing was also explored using buffered oxide etchant and diluted HF. Etch rates of 1200 and 2000 Å/min in dilute HF solution were obtained for TiO@sub 2@ and SiO@sub 2@, respectively. However, a significant etch-undercut of the structure and delamination at the SiO@sub 2@/TiO@sub 2@ interfaces were observed with the wet chemical etching due the internal stress between the SiO@sub 2@/TiO@sub 2@ layers.