Before revision: Silicon wafer diameters are larger (typically 8" or 12 " compared with 4" or 6 " for GaAs) and the wafer costs are lower, contributing to a less expensive IC.
After revision: Silicon wafer diameters are larger (typically 8" to 15 " compared with 4" to 8 " for GaAs) and the wafer costs are lower, contributing to a less expensive IC.