Elimination of interface defects in mismatched epilayers by a reduction in growth area

We have eliminated interface defects from the mismatched Ino.()S GaO 95 As/ (001) GaAs interface by controlling the size of the growth area. 2-Jim-high pillars with different lateral shapes and dimensions were defined within the GaAs substrate before the molecular beam epitaxial growth of 3500 A of Ino.05 Gao,!" As, greater than four times the critical thickness. On the pillars, the linear density of misfit dislocations was reduced from > 5000 dislocations!cm for large (several hundred pm lateral dimensions) growth areas to nearly zero for 25 f.lm lateral dimensions. The dislocation density remains less than 800 dislocations/em for lateral dimensions up to 100 ,urn. We find that there is also a decrease in dislocation density in narrow channels between the pillars; therefore, the pillars also block the glide of misfit dislocations.