Probe for testing an electrical property of a test sample

A system for testing an electrical property of a test sample, said system comprising:

• a probe having a probe body defining a planar surface for supporting a first cantilever, and a first thermal detector,
• said first cantilever extending from said probe body in a co-planar relationship with respect to said planar surface between a first proximal end supported by said planar surface and a first distal end opposite to said first proximal end,
• said first cantilever having a cantilever surface supporting a first contact probe,
• said first thermal detector extending from said probe body in a co-planar relationship with respect to said planar surface between a second proximal end supported by said planar surface, and a second distal end opposite said second proximal end,
• said first thermal detector having a detector surface supporting an electrical conductor with a temperature dependent electrical resistance, said system further comprising:
• a heater or a cooler for establishing a temperature difference between said electrical conductor and said test sample,
• a power source interconnected with said electrical conductor for injecting a current in said temperature dependent electrical conductor,
• an actuator for moving said probe towards said test sample, and
• an electronic circuit interconnected with said electrical conductor for measuring said temperature dependent electrical resistance, and for comparing said temperature dependent electrical resistance with a threshold value.

A method of normalizing a measurement of a thermal detector measuring a proximity between said thermal detector and a test sample, said method comprising:

• providing a probe having a probe body defining a planar surface for supporting a thermal detector,
• said thermal detector extending from said probe body in a co-planar relationship with respect to said planar surface between a proximal end supported by said planar surface, and a distal end opposite said proximal end,
• said thermal detector defining a detector geometry with a first geometric dimension, and having a detector surface supporting an electrical conductor with a temperature dependent electrical resistance,
• said method further comprising:
• injecting a current in said electrical conductor,
• providing an electronic circuit, connecting said electronic circuit to said electrical conductor and measuring said electrical resistance by means of said electrical circuit for providing an output, and
• performing a mathematical normalization of said output by said first geometric dimension such that said output being normalized with respect to said detector geometry.

A method of determining a proximity between a thermal detector and a test sample, said method comprising:

• providing a probe having a probe body defining a planar surface for supporting a thermal detector,
• said thermal detector extending from said probe body in a co-planar relationship with respect to said planar surface between a proximal end supported by said planar surface, and a distal end opposite said proximal end,
• said thermal detector defining a detector geometry with a first geometric dimension, and having a detector surface supporting an electrical conductor with a temperature dependent electrical resistance,
• said method further comprising:
• establishing a temperature difference between said electrical conductor and said test sample, injecting an alternating current with a first frequency in said electrical conductor,
• providing an electronic circuit, connecting said electrical circuit to said electrical conductor, measuring said electrical resistance by means of said electronic circuit and providing an output while moving said probe towards said test sample,
• providing a filter with a cut off frequency lower than a second harmonic of said first frequency, filtering said output by means of said high pass filter, and providing a filtered signal, and
• using said filtered signal as a measure for the proximity between said thermal detector and said test sample.