Experimental requirements for the measurement of excess carrier lifetime in semiconductors using microwave techniques

Experimental requirements for an accurate evaluation of the excess carriers lifetime in semiconductors using nondestructive microwave reflection techniques are presented. A relationship between the observed exponential decay time constant and the excess carrier lifetime is derived. It is shown that the microwave transient decay time constant could be either the lifetime or half of the lifetime depending on the arrangement of the measurement setup. The theory of the lifetime measurement has been corroborated by the microwave measurements taken on silicon and semiinsulating gallium arsenide (Si-GaAs) wafers and by an independent photovoltage decay method on silicon solar cells