Micro-machined dielectrically isolated (MMDI) wafer technology [SOI]

This paper describes a new economical alternative to costly bonded silicon-on-insulator (BSOI) wafers in which dielectrically isolated wafers are fabricated from single bulk silicon wafers. Initial processing involves trench etching through a single wafer to a predefined depth using micro-machining tools. The trenches are filled with an insulator to provide lateral dielectric isolation. Standard semiconductor processing is performed. The back side of the silicon is then removed to at least the level of the bottom of the trenches, and an insulating oxide is deposited on the back surface. We call this new technology micro-machined dielectric isolation (MMDI). This new technology reduces the cost of producing DI wafers by over 30% compared to BSOI technology, due to the reduction in the materials and the processing steps. Opto-electronic devices have been fabricated using MMDI technology with yields, performance, and reliability comparable to devices fabricated using the standard BSOI production process.