Research On The Coupling Effect Of HCI And TID In PDSOI Devices

The technology of SOI(Silicon On Insulator)is the focus of research in the 1990 s.Compared with bulk Silicon devices,SOI devices have the advantages of high speed,low power consumption and anti-latch,and it is also recognized by the industry as one of the solutions to replace the existing monocrystalline Silicon materials in the era of nanotechnology.It is used in many fields such as aerospace.But as the feature sizes of devices continues to decrease,the working voltage of device without such as scaling,channel transverse electric field increases gradually,make the hot carrier effect causes the degeneration of the device is more and more serious,for SOI device,because buried layer BOX,the hot carrier effect became more serious,at the same time in outer space radiation environment,The devices also face the influence of irradiation,which poses a more serious challenge to the reliability of devices themselves.Based on the above situation,this paper studied the thermal carrier effect and total dose effect of PDSOI devices,and also analyzed the coupling mechanism of HCI effect and TID effect.The experimental samples used in this paper are based on 0.13μm PDSOI process and have different device structures(T-shaped gate,H-shaped gate and floating gate)and aspect ratio for comparative analysis.Firstly,the TCAD tool Sentaurus software was used to build a twodimensional structure model of 0.13μm device,and a corresponding physical model was added based on the physical mechanism of hot carrier effect.Then,the thermal carrier effect acceleration stress of the device is tested,and the simulation results are compared with the experimental data.The effects of different drain stress and voltage,different aspect ratio,different temperature and different device structure on the degradation of hot carrier effect are studied.The results show that the degradation of HCI effect becomes more serious with the decrease of device size,and the degradation of hot carrier effect is also affected by temperature and different device structure.Then,the thermal carrier life of t-gate with width/length ratio of 0.5μm/0.18μm is predicted,and the failure life of t-gate under normal working conditions is evaluated.Then total dose irradiation experiment was carried out to study the effect of different bias states on the total dose effect of the device.The analysis of the experimental results shows that for each bias state(ON,OFF and TG),the output characteristic curve and transfer characteristic curve of the device are negative drift first and then positive drift,but the overall trend is positive drift.For different electrical characteristic parameters,the parameter drift is also different in different bias states.For example,the threshold voltage VT degrades most seriously in the open state(ON),and the saturation leakage current degrades most seriously in the OFF state(OFF).Finally,the coupling mechanism of total dose effect and thermal carrier effect is studied.In MOS devices,threshold voltage VT is one of the most important characteristic parameters.Devices in the open state(ON)with the most serious degradation of threshold voltage VT in the total dose irradiation experiment and devices with the same size structure that are not irradiated are selected to conduct the thermal carrier experiment at the same time,and the experimental results are analyzed.The degradation of the electrical properties of the device after irradiation is more serious,which indicates that the total dose irradiation can promote the thermal carrier effect of the device.