星载高速跨阻放大器电离总剂量效应研究

Impact of TID on Ultrahigh Speed Operational Amplifier on satellite

摘要:

为得到卫星搭载的高速跨阻运算放大器在星载环境中长时间工作后的性能变化情况,对3款增益带宽积大于1GHz的高速跨阻放大器芯片关键特征参数的电离总剂量损伤特性及变化规律进行了试验研究。辐照试验在60Coγ射线源上采用高温加速评估的方法完成,辐照到放大器芯片上的剂量率为(0.3~0.5) Gy(Si)/s。试验后分析了放大器芯片输出偏置、输出噪声和带宽等关键电参数在辐照前后及高温(85℃±6℃)退火前后的特性,讨论了引起电参数变化的机理。结果表明,经过两轮150 Gy(Si)剂量辐照及高温退火后,放大器芯片的输出偏置和输出噪声水平无明显变化,时域脉冲响应正常,-3dB带宽减小了3%左右。带宽为3款高速跨阻放大器芯片的辐射敏感参数,其变化与电离辐射在SiO2/Si界面引起正电荷建立和界面态直接相关。辐照后的芯片仍然能够满足高带宽测试情况下的需求,150 Gy(Si)为电参数和功能合格的累积剂量。

Abstract:

With the rapid development of the space technology, operational amplifier is widely used as the basic linear circuit in a satellite system. The earth’s natural space radiation environment consists of electrons, protons, and heavy ions, which can have serious effects on the surface properties of MOS and bipolar devices. The total ionizing dose effects can lead to degradation of electrical parameters such as threshold voltage shift, channel mobility degradation, and gain degradation. With the development of semiconductor devices in the direction of small size, the effects are enhanced and the reliability of semiconductor devices is decreasing. It is important to understand the total ionizing dose effects on spacecraft operational amplifier. As a basic linear circuit, operational amplifiers are widely used in space systems. In recent years, many researches have been done on the damage characteristics of operational amplifiers in different radiation environments, different temperatures and different dose rates. Many works are limited to low-speed operational amplifiers with gain bandwidth product (GBW) less than 1GHz. In practical application, the signal may have a high frequency component, which puts forward a high demand for the bandwidth of the system.