SRAM Anti-single-particle Hardening Design

As the control center of electronic devices, integrated circuit obtains a wide range of applications. Its security and stability has attracted increasing attention from all walks of life. However, IC is susceptible to be damaged by high-energy particles radiation in space, especially SRAM which acts as a data carrier is particularly vulnerable in complex radiation environment. Nearly 20 years, SRAM radiation hardened technology has made great program. It played a protective role in a variety of particle radiation environment to SRAM. This paper researches and summarizes the existing hardening technology, based on Double Interlocked Storage Cell DICE, proposes a new structure DDICE(Delay DICE) which can resist single-particle radiation in full states. Then designs an anti-Single Event hardened SRAM with the new structural cell. Finally we make functional verification and anti-single-particle effects validation to the SRAM.The main work of this paper is as follows:1. A detailed theoretical study on the space radiation environment has been made at the first place. Then we analyze the mechanism of various radiation effects of SRAM memory cell and sum up the existing hardening technology, such as resistance hardening, circuit design hardening, error correction coding and put forward the deficiencies.2. We introduce designing ideas of the new SRAM memory cell, and designed DDICE SRAM memory cell structure, using delay and filtering techniques, which is immune to the single-particle radiation in dynamic read write states and can filter out 1ns reverse pulse.3. SRAM peripheral circuits supporting DDICE cell is researched and designed. Based on full-custom circuit design steps, we designed a hardened SRAM with a capacity of 128 Kb, including schematic design, Pre-simulation, layout, Post-simulation, DRC and LVS, parameter extraction and verification.4. Finally, we did timing and functional simulation to the newly designed SRAM layout, and verified the ability of anti-single-particle effects. This structure has similar effects with DICE in static storage and the Linear Energy Transfer(LET) can reach 37.7218 2Me V ×cm/ mg. The value of LET in writing state can reach 26.1708 2 Me V ×cm/ mgand exceed 37.6351 2 Me V ×cm/ mg in the reading state, which is much higher than DICE`s 6.7511 2Me V ×cm/ mg in reading state and 6.6662 2 Me V ×cm/ mg in writing state. Compared with six tubes SRAM and DICE, the ability of anti-single-particle effects significantly improved. The average power consumption is about 11.96 m W.