单片微波集成电路(MMIC)是通过在共用半绝缘衬底(现用GaAs)上装配无源和有源元件制成的。今天,GaAs MMIC因其集成度高、电路功能多、频带宽度极大而进入微波通信和高频测量系统市场。GaAs MMIC遗留下来的关键问题之一是可靠性与器件性能的关系、电路的温度稳定性、互连以及引线键合、封装等等。当然,电路的有源和无源元件的可靠性一直是头等重要的。 MMIC的典型有源元件是砷化镓金属半导体场效应晶体管(GaAs MESFET)和高电子迁移率晶体管(HEMT)。对有源元件的可靠性曾通过在dc或RF偏压和高温条件下的寿命试验作过调查。共同报导的在dc偏压条件下的退化是:1)漏—源电流I_(dss)减小,2)夹断电压V_P下降,3)栅极漏电流增大。当施加RF偏压时,元件会因增益下降而有退化倾向。并伴随着噪声系数加大。此外,还发现金属栅极和接点间形成极间金属通道,结果造成元件因短路而失效。按适当规定的失效判据(通常是I_(dss)或增益变小的一定百分率),就可确定其寿命时间。失效分布假定为对数正态分布,在中等沟道温度范围(130～200℃)内已获得10~7～10~8h MT-TF。各种仪器检测方法,包括扫描光学显微镜、俄歇、能量弥散χ射线光谱学分析(EDXA)和二次离子质谱学分析,都已用来识别上述失效原因。现在可以相信,GaAs FET Monolithic microwave integrated circuits (MMICs) are made by assembling passive and active components on a common semi-insulating substrate (active GaAs). Today, GaAs MMIC enters the microwave communications and high frequency measurement systems market due to its high level of integration, versatile circuits, and large bandwidth. One of the key issues left behind by GaAs MMICs is reliability versus device performance, circuit temperature stability, interconnect, and wire bonding, packaging, and more. Of course, the reliability of the active and passive components of the circuit has always been of paramount importance. Typical active components for MMICs are GaAs MESFETs and HEMTs. Reliability of active components has been investigated by life tests at dc or RF bias and high temperatures. Commonly reported degenerations under dc bias conditions are: 1) a decrease in drain-source current I_ (dss), 2) a decrease in pinch-off voltage V_P, and 3) an increase in gate leakage current. When RF bias is applied, the component tends to degrade due to gain degradation. Accompanied by increased noise figure. In addition, it was found that the intermetallic metal path was formed between the metal gate and the contact, with the result that the device failed due to a short circuit. According to the appropriate failure criteria (usually I_ (dss) or gain a certain percentage of smaller), you can determine the life time. The failure distribution is assumed to be a logarithmic normal distribution, and MT-TF has been obtained for 10-7 to 10-8 hours at a medium channel temperature (130-200C). A variety of instrumental detection methods, including scanning optical microscopy, Auger, energy dispersive X-ray spectroscopy (EDXA) and secondary ion mass spectrometry, have been used to identify the causes of the above failures. Now you can believe that GaAs FET