Deep Level Transient Spectroscopy (DLTS) and Laplace DLTS (LDLTS) have been applied to MOVPE‐grown n‐type GaN, grown at 1020 °C on c‐plane sapphire. DLTS measured up to 600 K initially recorded three peaks due to electron emission. However, when the next rate window was sampled immediately afterwards, the DLTS scan showed a large negative peak which dominated the scan at 410K. The polarity of the feature means that this is due to hole emission. An electron trap initially present at 400 K in the DLTS spectrum gradually disappeared up to a measurement temperature of 520 K; beyond this the hole trap was observed. It then remained detectable by DLTS for up to one week, although cooling under bias decreased its intensity severely. LDLTS reveals that this hole trap is not a simple point defect as it has three emission rates. It is discussed in the context of the VGa‐ON(x) defect, where different emission rates present could reflect VGa complexed with different numbers of O atoms. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Deep level transient spectroscopy (DLTS) and high resolution Laplace DLTS (LDLTS) have been applied to p-type Czochralski silicon that contains dislocations that have and that have not been locked by oxygen. The stressinduced dislocations have been immobilized by oxygen during heat treatment, which prohibits glide under certain applied shear stresses. The DLTS spectra show typical broad features between 100 and 320 K, characteristic of those seen in other dislocated silicon reported in the literature, and several components are present in the LDLTS spectra. In addition, DLTS spectra show a sharp narrow peak at 40 K at a rate window of 200 s −1 in the case of the locked dislocations, but not in the case of the sample where there is no oxygen locking. LDLTS shows that this deep level consists of more than one component and it is proposed that this peak is likely to be due to electrical activity associated with oxygen at the dislocation core. For hole emission at temperatures above 100 K, in the sample with unlocked dislocations, LDLTS detects a change of the emission rate of the carriers from some, but not all, of the components of the broad peak when the LDLTS fill pulse length is changed. This change is ascribed to band edge modification as the electronic states associated with the dislocation charge up during the fill pulse, and causes local electric field-driven emission of trapped charge during the reverse bias phase of the measurement. The LDLTS features which remain constant with fill pulse are proposed to be due to point defects in the material, which are not physically near dislocations.