Determination of bandgap in SiGe strained layers using a pn heterojunction C-V

A pn heterojunction C-V technique used to determine the bandgap of SiGe strained layers is presented in this paper. The SiGe bandgap is analyzed and calculated by acguiring the built-in potential and discontinuities of valence and conduction bands, according to the C-V profile of the stained SiGe/Si pn heterojunction. This technique is much more convenient and the experimental results agree very well with the theoretical and published calculations, indicating that the method is correct. This method is suitable for not only the bandgap of the single SiGe/Si pn heterojunctions, but also that of the SiGe/Si devices with SiGe/Si pn heterojunctions.