Dislocation behavior in InGaN/GaN multi-quantum-well structure grown by metalorganic chemical vapor deposition

Propagation characteristics of dislocations were investigated in InGaN/GaN multi-quantum-well structures grown by metalorganic chemical vapor deposition. Threading dislocations with Burgers vector of b=[(1) over bar(1) over bar 20], emerged from the GaN buffer region, change their glide plane from normal to parallel to the growth plane when they meet InGaN wells. Dislocations gliding on the growth planes were pinned by quantum dots leaving two possible ways of propagation, changing their glide plane back to normal to the growth plane, [10 (1) over bar0], or extending loop shape pinned both ends by the quantum dots. Indium-rich quantum dots were formed on the InGaN quantum-well layers with size of 30+/-25 nm in diameter. It was estimated that the critical size of quantum dots to pin the dislocations is 30 nm. (C) 2002 American Institute of Physics.