Defect-level analysis of semiconductors by a new differential evaluation ofn(1/T)-characteristics

A new method for the defect-level analysis of extrinsic semiconductors is described. Provided that the defect-level concentration is not too large and the temperature is not too low, the Fermi levelE _F is shifted with increasing temperature from a position near the conduction (or valence) band towards the middle of the forbidden gap monotonously. Thus majority carriers are emitted into the conduction (or valence) band from the defect levels successively. If for a small increment of the temperature the Fermi levelE _F is shifted by ΔE _F and the concentration of free majority carriers is increased by Δn, then the ratio Δn/ΔE _F is a measure of the defect-level concentration within ΔE _F . Furthermore we discuss how this analysis is influenced by additional defect levels outside the range over which the Fermi energy can be shifted by variation of the temperature.