TY - JOUR
T1 - In situ spectroscopic ellipsometry studies of electron cyclotron resonance (ECR) plasma etching of oxides of silicon and GaAs
AU - Ianno, N. J.
AU - Nafis, S.
AU - Snyder, Paul G.
AU - Johs, Blaine
AU - Woollam, John A.
N1 - Funding Information:
This work was supported in part by the LIS Army Strategic Defense Command, grant No. I)ASG 6(}-92-C0028.
PY - 1993/1
Y1 - 1993/1
N2 - In situ spectroscopic ellipsometry (SE) covering the spectral range from 280 to 1000 nm was performed during RF bias assisted electron cyclotron resonance (ECR) etching of SiO2, GaAs oxide, silicon, and GaAs by a CCl2F2/O2 mixture. The etch rate of SiO2/Si samples as a function of RF bias power, and total pressure was then measured, in situ, for a constant ECR power of 175 W, and CCl2F2/O2 flow rate ratio of 1 3 by performing SE at selected wavelengths most sensitive to changes in SiO2 thickness. A wide range of etch parameters can be investigated without changing samples by employing a relatively thick SiO2 layer. This allows rapid optimization of the etch parameters, and can also provide accurate endpoint detection in the face of a time-dependent etch rate. Ellipsometric monitoring of bulk silicon and GaAs samples cannot provide in situ etch rates, however, insight into the etch mechanism may be gained by observing the effect of the etch process on the native oxide layer, surface roughness, and in the case of GaAs, on the surface stoichiometry.
AB - In situ spectroscopic ellipsometry (SE) covering the spectral range from 280 to 1000 nm was performed during RF bias assisted electron cyclotron resonance (ECR) etching of SiO2, GaAs oxide, silicon, and GaAs by a CCl2F2/O2 mixture. The etch rate of SiO2/Si samples as a function of RF bias power, and total pressure was then measured, in situ, for a constant ECR power of 175 W, and CCl2F2/O2 flow rate ratio of 1 3 by performing SE at selected wavelengths most sensitive to changes in SiO2 thickness. A wide range of etch parameters can be investigated without changing samples by employing a relatively thick SiO2 layer. This allows rapid optimization of the etch parameters, and can also provide accurate endpoint detection in the face of a time-dependent etch rate. Ellipsometric monitoring of bulk silicon and GaAs samples cannot provide in situ etch rates, however, insight into the etch mechanism may be gained by observing the effect of the etch process on the native oxide layer, surface roughness, and in the case of GaAs, on the surface stoichiometry.
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U2 - 10.1016/0169-4332(93)90057-I
DO - 10.1016/0169-4332(93)90057-I
M3 - Article
AN - SCOPUS:0027206236
SN - 0169-4332
VL - 63
SP - 17
EP - 21
JO - Applied Surface Science
JF - Applied Surface Science
IS - 1-4
ER -