THE DETERMINATION OF RIGID LATTICE SHIFTS ACROSS DELTA-DOPED LAYERS USING REGRESSIONAL ANALYSIS

We present a simplified approach for determining the rigid lattice shi ft across an interlayer from a high-resolution lattice image. The appr oach is illustrated through the analysis of delta-doped layers in Si a nd GaAs, for which the lattice shifts are measured to accuracies of be tter than +/- 7 pm. The results are compared with the predictions of c ontinuum elasticity theory, and some surprising discrepancies are note d. In particular, for Si delta-doping in GaAs the measured lattice con tractions do not follow the predicted linear increase with dopant conc entration and are much larger than the theory would predict. (C) 1998 Elsevier Science B.V. All rights reserved.