Four-point Probe Resistivity Noise Measurements of GaSb Layers

This paper concerns measurements and calculations of low frequency noise for semiconductor layers with four-probe electrodes. The measurements setup for the voltage noise cross-correlation method is described. The gain calculations for local resistance noise are performed to evaluate the contribution to total noise from different areas of the layer. It was shown, through numerical calculations and noise measurements, that in four-point probe specimens, with separated current and voltage terminals, the non-resistance noise of the contact and the resistance noise of the layer can be identified. The four-point probe method is used to find the low frequency resistance noise of the GaSb layer with a different doping type. For n-type and p-type GaSb layers with low carrier concentrations, the measured noise is dominated by the non-resistance noise contributions from contacts. Low frequency resistance noise was identified in high-doped GaSb layers (both types). At room temperature, such resistance noise in an n-type GaSb layer is significantly larger than for p-type GaSb with comparable doping concentration.