Carrier Depth Profile of Si/SiGe/Si n-p-n HBT Structural Materials Characterized by Electrochemical Capacitance-Voltage Method

Si/SiGe/Si n-p-n HBT structural materials have been grown by gas source molecular beam epitaxy with disilane, solid Ge, diborane and phosphine as sources. The materials are of good structural properties. The effectiveness of Electrochemical Capacitance-Voltage (ECV) technique on profiling the shallow doped layers of nanometer dimensions has been demonstrated. Compared with spreading resistance probe, the ECV technique is relatively easy to get the carrier distribution profile, especially for the Si/SiGe/Si HBT structural materials with shallow (≤50nm) base regions (p-type SiGe layer, Ge content about 0.2). The results show that n-p-n structures can be obtained by in situ doping.