Constant-resistance deep-level transient spectroscopy in Si and Ge JFET's

The recently introduced constant-resistance deep-level transient spectrosco py (CR-DLTS) was successfully applied to study virgin and radiation-damaged junction field-effect transistors (JFET's). We have studied three groups o f devices: commercially available discrete silicon JFET's; virgin and expos ed to high-level neutron radiation silicon JFET's, custom-made by using a m onolithic technology; and commercially available discrete germanium p-chann el JPET's. CR-DLTS is similar to both the conductance DLTS and to the const ant-capacitance variation (CC-DLTS). Unlike the conductance and current DLT S, it is independent of the transistor size and does not require simultaneo us measurement of the transconductance or the free-carrier mobility for cal culation of the trap concentration. Compared to the CC-DLTS, it measures on ly the traps inside the gate-controlled part of the space charge region. Co mparisons have also been made with the CC-DLTS and standard capacitance DLT S. In addition, possibilities for defect profiling in the channel have been demonstrated. CR-DLTS was found to be a simple, very sensitive, and device area-independent technique which is well suited for measurement of a wide range of deep level concentrations in transistors.