Semiconductor >Measurement Technology >JPV

JPV (Junction PhotoVoltage)

Semilab’s patented JPV (Junction PhotoVoltage) measurement technology is used to measure the sheet resistance of ion implanted layers, after anneal.  It works by inducing a voltage at a point on the junction between an implanted layer and a substrate.  The induced voltage causes current to flow radially.  By measuring how the voltage decays as the current flows radially, one can determine the sheet resistance.  If the resistivity is low, the voltage decays slowly.  If the resistivity is high, the voltage decays more quickly.

The voltage that stimulates the flow of current is created by light shining on the sample.  The effect is the same as the basis of a solar cell and is illustrated below.

The use of a chopped light source causes an ac change in the surface potential, which can be sensed via capacitive sensors positioned over the sample being measured. 

The schematic of the whole principle is as follows.


Via suitable calibration it is possible to convert the two signals on the capacitive electrodes into the sheet resistance of the implanted layer.

The JPV capability is available as a measurement option in the WT-2000 Multifunction Wafer Mapping System and in the WT-3000 Dual FOUP Wafer Mapping Tool .