Simulations and measurements of emitter properties in 5 kV Si PIN diodes

Emitter properties have been studied by comparing simulated and measured data of excess carrier concentration and surface potential in 5 kV Si PIN diodes. Comparison were made under forward conduction and turn-on for current densities in the range 30-300 A/cm² and for different depths and concentrations of the n⁺ and p⁺ emitters. The density of excess carriers were measured by the Free Carrier Absorption (FCA) technique as a function of depth and the surface potential by scanning a tungsten probe tip on the polished diode surfaces. The FCA measurements correlate well to simulated data, but discrepancies between simulated and measured data of the surface potential indicate the need for improved physical models