基于实际结温分布中小电流过趋热效应的验证

Verification of the Excessive Thermotaxis Effect of Low Current Based on Actual Junction Temperature Distribution

对于从红外热像图得到的实际的晶体管结温分布,通过热谱分析方法获得该温度分布对应的热谱曲线,进而建立了晶体管子管并联模型,并在此基础上,经过实验和理论计算证实了pn结中小电流过趋热效应存在的真实性.当结温分布不均匀时,对于通过pn结的电流,小电流比大电流更具有趋热性.即电流越小,高温区与低温区电流密度的比值越大,电流越集中在高温区,且集中区域的面积随着电流的减小而缩小.利用这一特性可以研究器件热电不稳定性,结温分布的不均匀性及不均匀度,峰值结温的估算等,这对于半导体器件可靠性分析具有重要的意义.

Using the junction temperature distribution as determined from infrared imaging, the thermal spectrum curve is obtained by thermal spectrum analysis for use in creating a ＂sub-transistors in parallel connection＂ model. Based on the model, from theoretical calculation and experiment, the validity of the excessive thermotaxis effect of low current is verified. For current passing through a pn junction in a non-uniform temperature distribution,there is much more thermotaxis at low current than at high current,i, e. ,with decreasing measured cur？ent, the ratio of the current density at high-temperature to that at low-temperature increases,and the effective area decreases. Based on these characteristics, the electro-thermal instability and the degree of uniformity of the junction temperature distribution can be studied. This has great significance for the reliability analysis of semiconductor devices.