双沟槽SiC金属-氧化物-半导体型场效应管重离子单粒子效应

Heavy ion single event effect in double-trench SiC metal-oxide-semiconductor field-effect transistors

本文针对第四代双沟槽型碳化硅场效应晶体管升展了不同源漏偏置电压下208 MeV锗离子辐照实验,分析了器件产生单粒子效应的物理机制.实验结果表明,辐照过程中随着初始偏置电压的增大,器件漏极电流增长更明显;在偏置电压为400 V时,重离子注量达到9×10^(4)ion/cm^(2),器件发生单粒子烧毁,在偏置电压为500 V时,重离子注量达到3×10^(4)ion/cm^(2),器件发生单粒子烧毁,单粒子烧毁阈值电压在器件额定工作电压的34%(400 V)以下.对辐照后器件进行栅特性测试,辐照过程中偏置电压为100 V的器件泄漏电流无明显变化;200 V和300 V时,器件的栅极泄漏电流和漏极泄漏电流都增大.结合TCAD仿真模拟进一步分析器件单粒子效应微观机制,结果表明在低偏压下,泄漏电流增大是因为电场集中在栅氧化层的拐角处,导致了氧化层的损伤;在高偏压下,辐照过程中N-外延层和N+衬底交界处发生的电场强度增大,引起显著的碰撞电离,由碰撞电离产生的局域大电流密度导致晶格温度超过碳化硅的熔点,最终引起单粒子烧毁.

In this paper,experiments on 208 MeV Ge ion irradiation with different source-drain bias voltages are carried out for the double-trench SiC metal-oxide-semiconductor field-effect transistors,and the physical mechanism of the single event effect is analyzed.The experimental results show that the drain leakage current of the device increases more obviously with the increase of the initial bias voltage during irradiation.When the bias voltage is 400 V during irradiation,the device has a single event burned at a fluence of 9×10^(4) ion/cm^(2),and when the bias voltage is 500 V,the device has a single event burned at a fluence of 3×10^(4) ion/cm^(2),so when the LET value is 37.3 MeV·cm^(2)/mg,the SEB threshold of DUT does not exceed 400 V,which is lower than 34%of the rated operational voltage.The post gate-characteristics test results show that the leakage current of the device with a bias voltage of 100 V does not change significantly during irradiation.When the bias voltage is 200 V,the gate leakage and the drain leakage of the device both increase,so do they when the bias voltage is 300 V,which is positively related to bias voltage.In order to further analyze the single particle effect mechanism of device,the simulation is conducted by using TCAD tool.The simulation results show that at low bias voltage,the heavy ion incident device generates electron-hole pairs,the electrons are quickly swept out,and the holes accumulate at the gate oxygen corner under the effect of the electric field,which combines the source-drain bias voltage,leading to the formation of leakage current channels in the gate oxygen layer.The simulation results also show that at high bias voltage,the electrons generated by the incident heavy ion move towards the junction of the N-drift layer and the N+substrate under the effect of the electric field,which further increases the electric field strength and causes significant impact ionization.The local high current density generated by the impact ionization and the load large electric field causes the lattice temperature to exceed the melting point of silicon carbide,causing single event burnout.This work provides a reference and support for studying the radiation effect mechanism and putting silicon carbide power devices into aerospace applications.