Improved breakdown for SOI MOSFETs fabricated in electron-beam recrystallized polysilicon

The breakdown mechanism for SOI (silicon-on-insulator) n-type MOSFETs is discussed. It is proposed that by reducing the channel lateral electric field at the drain that breakdown can be increased. A two-dimensional finite-element modeling program was used to design a treble diffused drain-sources (TDD) implant profile which would increase the breakdown voltage. The modeling showed that a linearly graded structure would lower the electric field in the channel and would subsequently increase drain-source breakdown voltage by over 20%. Transistors fabricated in e-beam recrystallized material verified these predictions.>