Critical analysis of weighting functions for the deep level transient spectroscopy of semiconductors

Abstract

More than 20 weighting functions proposed for DLTS are critically compared. It is shown that the variety of DLTS peak widths of different weighting functions was primarily due to the variety of shapes of the high-temperature side of the peak. A refinement of the classification scheme of the weighting functions is proposed. It is shown that the high-temperature side of the DLTS peak can be made independent of the weighting function, by considering the delay time between the end of the filling pulse and the beginning of the weighting function as an integral part of each weighting function. An optimum delay time (specific for each weighting function) is obtained by maximizing the figure of merit defined as the signal-to-noise ratio of the correlator divided by the DLTS peak width. Using the concept of optimum delay time, the functions can be classified into several groups according to their selectivity. The functions from one group differ only by their sensitivity, making it easy to select the functions with the best signal-to-noise ratios. In the second part of the paper, several misunderstandings concerning exponential correlators and double boxcars that frequently appear in the literature are revealed.

Influence of annealing atmosphere on formation of electrically-active defects in rutile TiO2

“…Filling pulses with an amplitude of 2 V to 4 V and a duration of 50 ms were employed. The DLTS signal was extracted from the acquired capacitanceversus-time transients using a lock-in weighting function 51 with six different rate windows in the range of (20 ms) À1 to (640 ms) À1 . A delay time of 5 ms and a temperature resolution of 1 K were used.…”

“…Here, DC is determined from the measured capacitance transients, 43,51,54 while C rb is the capacitance measured at the quiescent reverse bias voltage. N D is derived from CV measurements.…”

Formation of donor and acceptor states of the divacancy–oxygen centre in p-type Cz-silicon

“…The GS4 weighting function was first suggested by Istratov in 1997 and derived by Stehfest-Gaver algorithm. [17,18] It gives better energy resolution with higher capability of separating the peaks but has a poorer signal-to-noise ratio. The GS4 weighting function is given as A difference between lock-in and GS4 is shown in Fig 3.5.…”

Electron and Hole Trap Signal with Similar Defect Parameters in Chalcopyrite Based Solar Cells

“…The transients were normalized to the respective equilibrium capacitance. Afterwards, they have been evaluated using the double-boxcar weighting function, in order to obtain the usual DLTS signal versus temperature graphs [10].…”