SCALING OF SI AND GAAS TRENCH ETCH RATES WITH ASPECT RATIO, FEATURE WIDTH, AND SUBSTRATE-TEMPERATURE

The dependence of Si and GaAs trench rates on aspect ratio, french width and substrate temperature was investigated under constant Ar/Cl2 electron cyclotron resonance plasma conditions. Results showed that at higher substrate temperature, etching rates for both Si and GaAs scaled only with aspect ratio. At lower temperature (-45°C), etching rates scaled with both aspect ratio and trench width. The dependence of Si etch rate on feature dimension, however, was stronger than that of GaAs.