Four Dimensions' Four Point Probe Selection Guide

Type	Application	Material	Tip Radius @ Contact Area Radius	Force
Type-A	Metal films, ITO, amorphous Si, poly silicon, SOI, bulk substrates	Tungsten Carbide	25 um or 45um	90-200g
Type-B	General Purpose: medium to thick epitaxial layers, diffused layers, metal films, implants 2-10 microns	Tungsten Carbide	100um	90-200g
Type-M	epitaxial, diffused and ion implanted layers (500 A to 5 um), especially very shallow ion implanted layers	Tungsten Carbide	300um @ 120um	90-200g
Type-N	Very shallow implants	Tungsten Carbide	500um	90-200g

Type-C	III-V compound semiconductors, e.g. GaAs, InAs	Osmium	100um	60-150g
Mercury	Ultra shallow implants, ultra thin layers	Mercury		~0

Custom	Customized tips	various	various

We are happy to help you with the probe head selection for your material's needs. Please contact us at info@4dimensions.com for assistance.