Apparatus and methods of measuring minority carrier lifetime using a liquid probe

An apparatus for measuring the minority carrier lifetime of a semiconductor material comprising:

• a first conductive liquid probe providing for making temporary contact with a surface of a semiconductor material at a first location to form a rectifying junction;
• a second junction electrically coupled to the semiconductor material at a second location, wherein the first location and the second location are physically separated;
• a power supply in electrical communication with the first conductive liquid probe providing for the application of a forward bias to the rectifying junction, causing minority carrier injection in the semiconductor material;
• a capacitance measuring module coupled to the rectifying junction and the second junction;
• a processor in electrical communication with the first conductive liquid probe and the capacitance measuring module;
• and
• a non-transitory machine readable medium having encoded thereon a set of instructions executable by the processor to perform one or more operations, the set of instructions comprising instructions to:
• measure a total capacitance between the rectifying junction and the second junction as a function of frequency;
• determine an inflection frequency of the total capacitance as a function of frequency;
• and
• determine a minority carrier lifetime of the semiconductor material from the inflection frequency of the total capacitance as a function of frequency.

An apparatus for measuring minority carrier lifetimes in a semiconductor material, the apparatus comprising:

• a semiconductor material comprising a surface;
• a rectifying junction formed at a first location of the surface, the rectifying junction comprising a probe in contact with the surface via a conductive liquid;
• a second junction electrically coupled to the semiconductor material at a second location physically separated from the first location;
• a power supply coupled to the probe, the power supply configured to apply a forward bias across the rectifying junction such that minority carrier injection into the semiconductor material occurs and a depletion region within the semiconductor material forms, wherein the power supply sweeps a frequency of the forward bias across a frequency range;
• a capacitance module coupled to the rectifying junction and the second junction, the capacitance probe outputting series of total capacitance measurements as a function of the frequency applied by the power supply;
• and
• a processor coupled to the capacitance module, wherein the processor outputs a calculated minority carrier lifetime of the semiconductor material by identifying an inflection point in the series of total capacitance measurements.