A Study of Damage Induced in In0.52Al0.48As Surface by Reactive Ion Etching
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Photoreflectance (PR), Raman scatter (RS), and photoluminescence (PL) experiments have been carried out to characterize the In0.52Al0.48As surface exposed to plasma with a gas of methane-hydrogen. PR spectra indicate that reactive ion etching (RIE) causes damage such as nonradiative recombination centers, scattering centers, and defects leading to the decrease of signal intensity, broaden linewidth and red shift of the transitions by increasing the rf power. In the Raman scattering study, RIE causes damage against InAs-like and AlAs-like longitudinal optic (LO) modes vibration. As the rf power increased, the maximum of two LO modes shifts towards lower frequency and the line shape becomes increasingly asymmetric. Also, the degraded intensity causes by disorder and point defects gradually with increasing rf power. Corresponding PL measurements showed that the transition energies red-shift with increasing the rf power. In addition, the spectral feature a broadens, and the intensity decreases with rf power more than 200 W. There is a good correlation of the PL, PR, and RS indicating that these methods can be used as sensitive evaluate for near surface damage of the epilayer.
- Jpn J Appl Phys
Jpn J Appl Phys 35(2A), 533-536, 1996-02-15
INSTITUTE OF PURE AND APPLIED PHYSICS