Hello,
The advantages of Si over Ge are:
=> Stable and strong material & crystal structure like diamond
=> Si has a wider bandgap than Ge
=> higher operating temperature (125-175 oC vs. ~85 oC) and thus become intrinsic at higher temp.
=> Si readily forms a native oxide (SiO2) high-quality insulator protects and “passivates” underlying circuitry helps in patterning useful for dopant masking.
=>Large variety of process steps possible without the problem of decomposition (as in the case of compound semiconductors)
=> Si is cheap and abundant
Paramjyothi