Modeling And Research On Annular Gate Device

The TID enhancement capability of the ICs increased as advanced integratecircuit technologies developed. However, the varieties of processes, wafers andproduct lines make greate difference between the commercial CMOS devices inintegrate circuit. It is need to take TID enhancement technologies to make sure thatdevices used in space radiation environment for long time.The mechanism of total ionizing dose and some consummate TID enhancementmethods have been introduced. An8kb static random access memory has beendesigned with annular gate device in this paper.Firstly, a universal method which can be used for most annular gate layouts tocalculate effective widths and some corrections for relevant parameters incommercial SPICE models have been proposed in this paper to solve the proplemthat commercial SPICE models can not be used in annular gate device simulations.Comparasions between the proposed model and the existing model and simulationsbetween SPICE and TCAD show a good accuracy of our model.Secondly, a study of the SMIC0.18μm stardand cell library has been done tomake sure that the row and column decoders of the designed SRAM can becompleted by Top-Down flow in digital IC design with annular gate devices. Threekinds of standard cell with annular gate structure have been designed in this paperand verifications show that the designed standard cells can be used by digital circuitsdesign tools.Finally, the layout design and verification of8kb SRAM have been completedwith the annular gate standard cells and other cells in SMIC0.18μm stardand celllibrary. The results show that the leaf cell of designed SRAM works correctly in10nsclock period.