GexSi1-x, strained layers can be fabricated by Ge implantation and solid-phase epitaxy and can be used in electronic devices to improve their performance. Several important materials science issues are addressed, including the effect of the strain on solid-phase-epitaxy, the effect of oxidation on the implanted Ge distribution, and the effect of Ge on the oxidation rate of Si. The potential of this process is demonstrated by comparing the performance of metal-oxidesemiconductor field-effect-transistors (MOSFETs) employing ion-beam synthesised GeSi strained layer channel regions with that of Si-only devices.

This study examined the effect of ion irradiation and subsequent thermal annealing on GeSi/Si strained-layer heterostructures. Comparison between samples irradiated at 253°C with low energy (23 keV) and high energy (1.0 MeV) Si ions showed that damage within the alloy layer increases the strain whereas irradiation through the layer/substrate interface decreases the strain. Loop-like defects formed at the GeSi/Si interface during high energy irradiation and interacting segments of these defects were shown to have edge character with Burgers vector a/2<110>. These defects are believed responsible for the observed strain relief. Irradiation was also shown to affect strain relaxation kinetics and defect morphologies during subsequent thermal annealing. For example, after annealing to 900°C, un-irradiated material contained thermally-induced misfit dislocations, while ion-irradiated samples showed no such dislocations.

A MBE growth procedure of epitaxial silicon layers is demonstrated which includes a special designed buried strained compositionally graded Si1−xGex layer. Upon thermal relaxation closed dislocation loops are formed in this Si1−xGex layer without altering the structure of the Si top layer. This dislocated layer is shown to getter contaminants in the Si top layer reducing the concentration of deep levels in this layer to ≈1 × 1012 cm−3.

The influence of implantation-induced non-stoichiometry on the electrical activation and depth distribution of Group IV (Ge and Sn) and VI (Se and Te) elements in InP has been investigated with a variety of analytical techniques. Electrical measurements indicate that P co-implantation can increase the electrical activation of the Group IV elements through reductions in amphoteric behaviour and dopant-defect complexes for Ge and Sn, respectively. The relative influence of P co-implantation increases as the dopant ion dose increases. Though others have demonstrated that co-implantation increases the electrical activation of Group II elements, similar observations were not apparent for Group VI elements, the latter attributed to the lack of Group VI element interstitial character.

Electrical activation and carrier mobility have been studied as a function of ion dose and annealing temperature for InP implanted with Group IV elements (Si, Ge and Sn). In general, electrical activation increases with decreasing ion dose and/or increasing annealing temperature. Si and Sn exhibit comparable activation and mobility, superior to that of Ge, over the ion dose and temperature range examined. The relative influences of implantation-induced non-stoichiometry and the amphoteric behaviour of the group IV elements have been investigated. For the latter, the amphoteric behavior of Ge > Si > Sn.

The chemical profiles of Zn, Ge, and Se implanted into InP at elevated temperatures have been measured with secondary ion mass spectrometry and correlated to the implantation damage as deduced from RBS/channeling measurements. An asymmetric broadening of the chemical profiles towards the bulk was found for implantation temperatures above 150°C. This effect is concluded to be due to impurity channeling during implantation.

The lattice location of ion implanted Ga, Ge, and Se in InP has been determined with a combined RBS/channeling-PIXE technique and correlated to the carrier concentration and mobility profiles obtained with differential Hall/resistivity measurements.

By combining RBS/channeling, Mössbauer spectroscopy, and TEM measurements on implanted Sn in Silicon, the solid solubility has been determined at 1025°C, 1075°C, and 1188°C to be respectively, 6.1 , 4.8 , 3.1·1020 cm-3.