Silicon-germanium—a promise into the future?

Comparing different semiconductor technologies and taking into account their actual performance/cost ratio, the current understanding is that the silicon technology is and will be the basis of IC fabrication also in the beginning of the next century. Due to new applications there is, however, a market’s demand to overcome the cutoff frequency limit inherent to silicon technology. Hitherto obtained results suggest that existing solutions may be challenged by SiGe or other silicon-based heterostructure devices. As an example of such heterostructure devices, in general, the first practical bandgap-engineered silicon device, namely, the SiGe heterojunction bipolar transistor, is discussed in more detail. However, to succeed commercially, the SiGe technology has to outperform the silicon technology and undersell the III–V technologies. To this end, the development of a heterojunction silicon-based CMOS technology will be of utmost importance. First results are encouraging and, hence, the very near future will probably show whether or not SiGe is a promise into the future.