Structure Design and Characteristics of Sense-Switch pFlash Devices

Abstract

Nonvolatile programmable switch is the base component of Flash-based Field-Programmable Gate Arrays (FPGAs), and its performance is the key to realize reconfigurable FPGA circuits. The Sense-Switch pFlash is a common floating gate device, which has the advantages of high integration, radiation hardness and high reliability. It is a better choice to realize radiation hardened Flash-based FPGA. The dumbbell and bar gate Sense-Switch pFlash devices are designed, and the theoretical analysis based on band-to-band tunneling induced hot electron (BBHE) and Fowler-Nordheim (FN) tunneling models is carried out, and the effect of improving the coupling coefficient on its performance is discussed by 0.13μm eFlash technology. It is found that the coupling coefficient can be effectively improved by increasing the poly1-interlayer-poly0 (PIP) capacitance in the field region, and the threshold window and ON/OFF-state characteristics can be significantly improved. Finally, the structure and programming/erasing methods of the Sense-Switch pFlash are optimized. Its endurance can reach 10,000 times, and it also has excellent retention characteristics, such as more than 1000h at 150°C. Therefore, it can be concluded that the dumbbell Sense-Switch pFlash is a better choice for Flash-based FPGAs.