高能中子诱发半导体器件产生单粒子翻转的模拟计算

Simulation of single event upset in semiconductor device induced by high energy neutrons

随着半导体及电子工艺技术的迅速发展,器件向着小尺度、低电压、低电荷、高集成度迈进,大气中子对航空及地面的电子系统造成的单粒子效应越来越显著.本文采用PHITS2.24蒙特卡罗程序及其事件发生器功能,借助于核反应模型与截面数据,验算了描述器件发生单粒子翻转能力的MBGR参数,并采用大气高能中子能谱,对SRAM器件的单粒子翻转率进行了计算与分析.这为我们今后模拟大气中子产生的各类单粒子效应提供了基本方法,也为将来开展相应的辐照实验提供了理论基础.

As the fast developments of the semiconductor devices and electronic systems, technology is trending towards smaller size, lower voltage, higher density and larger number of memory bits. These factors increase the single event effects （SEE） induced by atmospheric neutron radiation, both on the ground and in aircraft. Rapid testing the susceptibility of each new generation of electron devices to the neutron radiation effects is highly needed in many fields such as aviation, automotive, electronic medical device, and high reliability computer users and so on. Here we performed single event upset （SEU） simulations in a static random access memory （SRAM） cell under the irradiations of the atmosphere neutrons, using the PHITS2.24 Monte Carlo code. PHITS2.24 introduced the special feature of the event generator mode, which combined the evaluated nuclear data with the general evaporation mode （GEM）, so as to trace all correlations of ejectiles keeping the energy and the momentum conservation in a collision. PHITS outputs deposition energy distributions in the specified sensitive region, including energy deposit distributions caused by specific particles. By converting the deposition energy into the induced charge with the average required energy to produce an electron-hole pair （3.6 eV/（e-h pair））, the probabilities of the events can be calculated where the induced charge is greater than a critical charge. The MBGR parameters were validated and the SEU in a SRAM cell as a function of different critical charges were calculated. This kind of calculation supplies the basic method for the estimation of single event effects caused by atmosphere neutron irradiation. It is also very import for the future neutron irradiation experiment in semiconductor devices and electronic systems.