Researches On High-dose-rate Transient Ionizing Radiation Effects In Bulk Integrated Circuit

Integrated circuit can be caused signal upset and strong disturbance and circuit latch-up due to ionizing effect when exposed to a high dose rate radiation(HDR)environment.The cause of this failure phenomenon is that the unwanted photocurrent generated on silicon material due to ionizing effects.As the technologies scale down further in size and the integration of circuits increase rapidly,studying the response of Nano-electronic device radiated by HDR,and exploring the new mechanism which plays a significant role for hardness.The strong photocurrent is the direct cause which can cause upset and even burnout.The circuit response caused by high energy radiation is the main source of soft / hard errors for circuit applications in this environment.The doping files,the structure of the circuit,the bias setting and so on are changed with the change of the application environment.Investigating the effects of these factors on the photocurrent generated by the radiation will provide a theoretical basis for hardness design.In addition,due to the extensive use of bulk silicon devices in integrated circuit,taking full account of the influence of HDR on such devices has an important significance in radiation hardened design for bulk silicon integrated circuits.As one part of a research on anti-nuclear radiation project,the radiation responses of devices manufactured by 180 nm and 65 nm bulk silicon technology are studied.The influence of different conditions on the photocurrent is summarized.The main efforts and results are as follows:(1)Establish the HDR transient simulation platform in nanometer integrated circuits,which provides an important method in studying the transient ionizing effect.The 3-D device models are validated for 3-Ddevice model and spice model provided by SMIC,good agreement with the I-V characteristics is obtained.(2)The influence factor and mechanism on photocurrent have been revealed.Simulating different structure which is specialized in design,the results show that the parasitic bipolar effect is the main cause dominating the radiation responses of circuits,and some hardness methods are proposed.The influences of well doping concentration,depletion area and well contact on the transient ionizing effects are summarized.(3)The simulation results show that the recovery time of the supply voltage of core inverter is longer than that of the IO inverter after radiation.The full 0.18-micron process 3D device models of the core and IO inverter are established,and the function verification is carried out.It is shown that the different doping concentration affects the opening time of the parasitic bipolar effect,which results in the longer recovery time of supply voltage of core inverter.The radiation response of complex circuit is obtained through experiment,the experiment and simulation results are compared to verify the correctness of simulation.(4)The 4Mb SRAM of 180 nanometer technology experiment is presented at different dose rates.The radiation responses of the core supply voltage and the IO supply voltage are focused on.The experiment results shown that the restoration of supply voltage includes two processes,which are the disappearing process of photocurrent induced by radiation and the establishment process of circuit state.