双极器件中硅基区和锗硅基区的禁带变窄量

采用一种新的方法计算双极器件中离子注B硅基区和原位掺B的锗硅基区禁带变窄量．在器件基区的少子迁移率、多子迁移率和方块电阻已知的情况下，应用这种方法只需测量室温和液氮温度下的电学特性就可以获得禁带变窄量．这种方法从双极晶体管的集电极电流公式出发，利用VBE做自变量，在室温和液氮温度下测量器件的Gummel图，选取lnIC随VBE变化最为线性的一部分读出VBE及相应的IC数值，获得两条VBE-lnIC直线，通过求解两条直线的交点可以计算出基区的禁带变窄量ΔEG．利用这种方法测试了硅双极器件和锗硅基区双极器件，其基区禁带变窄量分别为41meV和125meV，这个测量结果与文献中的数值符合较好．

Electrical Determination of Bandgap Narrowing in Bipolar Transistors with Si and SiGe Bases

The apparent bandgap narrowing in bipolar transistors with ion implanted and epitaxial Si0．83Ge0．17 bases is measured using a new method．The bandgap narrowing is only obtained by measuring the electrical characteristics of the bipolar transistor at 300K and 77K under the condition of known μnB,μpB and RB of the transistor．According to the temperature dependence on the collect current IC(T),a graph of lnIC as a function of VBE is plotted based on the data extracted from the linear region of the Gummel plot when the temperature keeping constant．Two lines of lnIC-VBE at the temperature of 300K and 77K，respectively are obtained．At the intersection of two lines，the values of bandgap narrowing in Si and Si0．83Ge0．17 bases to be 41meV and 125meV，respectively，are got by calculation which are in good agreement with the measured ones in the reference．