（精）DLTS(深能级瞬态谱).ppt

Design, Development, and Testing of a Transient Capacitance Spectroscopy System Presented by: Kiril Simov Special thanks to: Dr. Tim Gfroerer Department of Physics, Davidson College Project supported by the American Chemical Society - Petroleum Research Fund Pioneers in Measurements of Depth Formation of Depletion Layer (Step 1) Formation of Depletion Layer (Step 2) Depletion Layer + Bias Depletion Layer + Bias in Equilibrium Energy diagram in the depletion region Carrier Trapping Carrier Escape What do we measure? Instrument Control Loop LabVIEW Control Panel LabVIEW Diagram Data Analysis Panel Conclusions and Future Work * * *picture taken from Serway, Raymond A., Beichner, Robert J. and Jewett, John W. Physics for Scientists and Engineers 5th Edition, Saunders College Publishing: Orlandon, FL, 2000 Motivation: Measuring the Depth of Defect –Related Traps in Semiconductors + + + + + + + + + + + + + + - + + + + + + + + + + + + + + + + - - - - - - - - - + + + + + + + + + + + + + + - + + + + + + + + + + + + + + + - - - - - - - - - Depletion Layer + + + + + + + + + + + + + + - + + + + + + + + + + + + + + + - - - - - - - - - Depletion Layer Bias Depletion Layer + + + + + + + + + + + + + + - + + + + + + + + + + + + + + + - - - - - - - - - Depletion Layer Bias Depletion Layer No bias With bias Energy Conductance Band Valence Band Defect Level Trap depth Energy - kT Low Temperature kT slow fast High Temperature - - Low Temp High Temp time Change in Capacitance Computer w/ LabVIEW Temperature Controller Circuit + Cap. Meter Oscilloscope Set temperature T Wait for T to stabilize Send bias pulse Measure capacitance C Obtain C vs. time graph from scope Next T Cryostat and SAMPLE 12 3 4 5 We have developed a versatile Transient Capacitance Spectroscopy (TCS) system using LabVIEW Accurate TCS spectra have been obtained using test diodes We will use the system next summer to characterize new devices in collaboration with the National Renewable Energy Laboratory Therm