Study On Device Characteristics And NBTI Effects Of FINFET

The information industry has developed rapidly since the mid-20th century and has become the largest industry in advanced countries.The semiconductor integrated circuit technology is the basis of the information industry.At present,the development of semiconductor integrated circuit technology has tended to be in the direction of high performance,low power consumption,and multi-functionalization,which has greatly accelerated the advancement of the information age in large-scale integrated circuits.In the course of development,the size of field-effect transistors has been continuously scaled down.When MOS devices evolve into nanometer dimensions,they face many challenges.Therefore,FINFET technology won the favor of a large number of semiconductor manufacturers with its high degree of integration.As manufacturers continue to optimize their FINFET devices,their feature sizes can continue to be reduced to a few nanometers,and their performance will increase even more than what they are now.Therefore,it is of great significance to study the improvement of the reliability of FINFET devices?In this thesis,the influence of the structural parameters of the FINFET device on the basic electrical characteristics and the degradation of the FINFET device under the influence of NBTI stress are studied in depth.The main work of this article:?1?A tri-gate SOI FINFET device was simulated and modeled.After the basic theoretical model of I-V characteristics was given,the effects of structural parameters?gate length,fin height,and fin width?on the I-V characteristics of the FINFET device were simulated.The increase of gate length will lead to the decrease of leakage current,while the increase of fin width and fin will increase the leakage current.By modifying the V_th model of planar MOS device,the V_th model of tri-gate FINFET is obtained and simulated by software.The process of changing the threshold voltage as the device structural parameters change is studied:As the gate length,fin width,and fin height increase,V_th tends to increase,decrease,and decrease,respectively,and is interpreted using the FINFET threshold voltage model.The trend of threshold voltage changes;the basic electrical characteristics of SOI FINFET devices were tested,and the influence of device geometry parameters on the threshold voltage was actually explored.?2?The NBTI degradation in P-type FINFET devices was tested experimentally.The overall situation of the NBTI effect of the FINFET device is described by the changes in the I-V characteristics of the FINFET device before and after the NBTI effect.Under the stress of NBTI,how the basic characteristics of the device to drift with NBTI stress time is studied.The effects of T and V_g on the V_thh drift are studied.Based on the above test and analysis results,the following conclusions are drawn:The static parameters of the FINFET device showed different degrees of degradation after NBTI stress.The specific situation is that the maximum transconductance Gmmax and the leakage current I_ds in the linear region decrease,and the negative drift of threshold voltage V_th,and the degradation is the most serious.Through the analysis of the drift of the device's static parameters with the NBTI stress time,the degradation of the device's threshold voltage V_th is used as a characterizing parameter to measure the parameter drift of the FINFET under NBTI stress conditions,and it is found that the device's threshold voltage becomes a power with the degradation of the stress time.Function degradation relations.The physical mechanism of the threshold voltage degradation is analyzed and it is concluded that for the FINFET,due to the extremely thin gate oxide layer,the increase of interface trap charge density is the key reason for the device parameter drift.