Single trench isolation for a 650 V SOI technology with low mechanical stress

The successful optimization and characterization of a deep trench isolation in a thick SOI process for operating voltages up to 650 V is reported. Different technologies were investigated to optimize the mechanical stress during wafer processing and to increase the breakdown voltage of a single trench configuration. Comprehensive electrical characterization was done to investigate achievable operating conditions and related reliability issues for thick oxide trench isolation layers. The most promising trench technology was choosen as a modular extension to an existing 650 V SOI BCD process.