STABILITY ANALYSIS OF CORRECTION SCHEMES FOR SPREADING RESISTANCE MEASUREMENTS

It is illustrated how the stability behaviour of a correction scheme for spreading resistance measurements can be analysed on the basis of its stability curves. This technique is applied on some recent schemes which incorporate a resistivity dependent probe radius. Their behaviour is compared with schemes implementing a fixed radius. From this analysis it follows precisely when the variable radius schemes considered will be stable or unstable. The primary cause for eventual instability is indicated and a new iteration approach is proposed which is able to remove this cause resulting in a drastically improved stability behaviour.