Substrate options and add-on process modules for monolithic RF silicon technology

Add-on process modules as enhancements of standard high-frequency silicon integration processes are discussed. Such modules can be added without any interference with the core process before (pre-process modules), during (mid-process modules), or after (post-process modules) the circuit integration. High-resistivity silicon substrates, the patterned metal ground shield, and bulk micromachining are presented as examples in each category, respectively.