Epitaxial layers of SiGe(C) have entered mainstream Si processing-forming base regions in heterojunction bipolar transistors. There are also exciting prospects that SiGe(C) could impact MOS technologies. In both cases heteroepitaxial layers enable very significant performance enhancements at device and circuit level. A related area and a familiar hot-potato is silicon epitaxy for device active regions in MOS technologies-where tightly controlled doping distributions can be incorporated to facilitate device function at deep submicron channel lengths. CVD is a preferred epitaxy deposition technique for production-currently LP-CVD and UHV-CVD dominate. Each of these techniques demand much of the technology and have their respective strengths and weaknesses. Issues regarding matrix and doping control, uniformity, blanket and selective area growth and throughput (a sensitive area) will be addressed. Also in the CVD portfolio is LEPE-CVD-a recent contender for the production arena which has the facility of being able to access very high deposition rates as required for example in depositing relaxed buffer layer material required as 'virtual substrates' for higher Ge content layers. SS-MBE, traditionally the favourite technique for research, also has distinct possibilities for development as a production tool. Here the issues relate primarily to throughput and system design, and (surprisingly) matrix profile control. These techniques will be outlined and reviewed along with issues which determine their development as the competition hots up in epitaxy, and as more complex and high Ge content structures are needed to progress Si technology to new performance heights and application areas.