METHOD AND APPARATUS FOR MEASUREMENT OF DEEP IMPURITY LEVEL IN SEMICONDUCTOR

PURPOSE:To measure a deep impurity level quantitatively in a noncontact and nondestructive manner by a method wherein a computation processing operation by a DLTS method is executed to a detection signal obtained by a measuring operation by a minority-carrier lifetime measuring method. CONSTITUTION:A signal waveform data is acquired sequentially at a plurality of temperatures in an arbitrary temperature range and is held in a storage part inside a computer 12. As signal acquisition conditions at this time, only the temperature of a specimen 1 under test is changed, and the condition to generate minoroty carriers and the condition of a position under test or the like are kept identical. Arbitrary times t1, t2 which make use of the minority-carrier excitation start time as the reference time are decided for individual signal waveforms corresponding to the plurality of temperatures; a difference DELTAS(T) in a signal value S(T, t) between the times t1, t2 of the signal waveforms at the individual temperatures T are found. In addition, a value W which is defined by a temperature Tm to make the DELTAS(T) maximum and by the t1, t2 is found. By combining a plurality of Tm's and W's, a correlation of in(W/Tm ) to (1/Tm) is found, and a plurality of levels are decided from its inclination.