Measurement Of Depletion Voltage And Leakage Current For Silicon Strip Detectors

Apparatus was assembled to measure the capacitance of, and current drawn by, a silicon strip diode detector over a range of applied reverse biased voltages. It was tested by using a variety of simple circuit components and simple diodes whose characteristics were known. The depletion voltage of the diodes was measured using values of capacitance measured over the range of voltages supplied.National Instruments Labview software was used to control the measurements in an automated routine designed, in part, by this author.Capacitances were measured using a digital LCR meter manufactured by Hewlett Packard (HP2842A). These values were taken at a range of LCR meter voltages and at frequencies of 10 kHz, 100 kHz and 1 MHz. Voltage biases were supplied and currents were measured using a Keithley 237 (a precision voltage and current supply).Two different silicon strip devices were measured. The depletion voltage was measured using one strip from each device and found to be 20±1 V for the first and 57±1 V for the second. The corresponding leakage currents were 4.5 nA and 1.43 µA.One silicon diode was measured before and after it was glued to a base plate with thermally conducting glue. The gluing did not effect the depletion voltage significantly. It did, however, effect the leakage current. This affect was greater at higher voltages.