Improved deep trench isolation breakdown voltage for SmartMOS

To achieve higher voltage analog and power devices, the deep trench isolation breakdown voltage must withstand the higher operating voltages. Optimization of deep trench etch to produce a straighter etch profile enable a void free poly filled trench, adding HF clean improve liner oxide film quality and changing liner oxidation process change the fill profile enable the oxide liner thickness to increase result in increase in the deep trench isolation (DTI) breakdown voltage.