Influence of Dopant Concentration on Dislocation Distributions in 150mm 4H SiC Wafers

Shifts in the spatial distribution of threading dislocations in 150 mm 4H SiC wafers were examined as a response to intentional changes in both the flow of the nitrogen source gas used to control resistivity during bulk crystal growth, and the growth rate. The density of threading edge and screw dislocations was found to be more evenly distributed in wafers produced under a high-growth rate, low-resistivity process. This result corresponded to a flattening of the resistivity distribution, and a ~34% reduction in on-and off-facet resistivity differential. The effect was attributed to regularized 4H island coalescence due to modulation of step terrace width.

Comparative Characteristics of GaAs and InAs Langmuir Evaporation - Monte Carlo Simulation

The process of GaAs and InAs substrates high-temperature annealing under the Langmuir evaporation conditions is studied by Monte Carlo simulation. The temperature range of gallium arsenide and indium arsenide congruent and incongruent evaporation are determined. It was demonstrated that the congruent evaporation temperature Tc is sensitive to the vicinal surface terrace width. The decrease of the terrace width results in a decrease in the congruent evaporation temperature. The Ga and In diffusion lengths along the (111)A and (111)B surfaces at congruent temperatures are estimated. The surface morphology transformation kinetic during high-temperature annealing is analyzed.

Theoretical insights into the effect of terrace width and step edge coverage on CO adsorption and dissociation over stepped Ni surfaces

We rationalized Ni(211) as a representative model for stepped surfaces and explored the effect of coverage on CO activation.