An Analog Circuit for Accurate OCVD Measurements
An electronic circuit for making accurate open-circuit voltage decay measurements is presented. The circuit overcomes the main limitations that occur in the standard method when used for carrier lifetime characterization because it realizes the ldquoopen-circuit conditionsrdquo of the device under test with an impedance higher than 100 MOmega and reduces the noise that is inherent in the differential operation of the method.
A novel measurement method of the spatial carrier lifetime profile based on the OCVD technique
Using an original test structure we show by numerical simulations that the open circuit voltage decay (OCVD) method can be improved to obtain the spatial profile of the /spl tau//sub PO/, /spl tau//sub NO/ lifetime parameters along the epilayer of n-n+ wafers. The test structure consists of a surface diode including an additional n/sup +/ region, where the diode is used to inject minority carriers within the epilayer, the sense region allows one to measure the diode voltage without the series resistance effect, and finally a positive voltage applied to the n+ substrate is used to electrically control the epilayer volume where carriers recombine.
Open circuit voltage decay lifetime of ion irradiated devices
Open circuit voltage decay method for measuring of excess carrier lifetime is shown to be effective for in-process checking of ion irradiated power diodes. 2.5 kV/100 A P-i-N diodes irradiated by helium ions with different irradiation energies and doses were used for presentation of capabilities of this method. Differences in carrier dynamics during the OCVD process between unirradiated and irradiated devices were studied by use of the device simulation in ATLAS.