Selective molecular beam epitaxy growth of quantum wire-dot coupled structures with novel high index facets for InGaAs single electron transistor arrays

For the InGaAs wire-dot-wire coupled structure arrays formed by selective molecular beam epitaxy (MBE) growth method on a specially designed patterned InP substrates, applicability to high density InGaAs single electron transistor (SET) arrays were investigated from the viewpoint of reproducibility of the selective MBE growth, size controllability and integration level. Appearance of the crater-like structure becomes a problem for reproducible formation of the InGaAs quantum wire-dot coupled structure. However, such a crater structure can be removed by appropriately adjusting growth condition and pattern sizes. The InGaAs wire size, the InGaAs dot size and the lateral width of the potential barrier were found to be controlled by the growth condition and the pattern geometry and can be reduced down to decananometer range. Highly integrated SET circuits with the device density larger than 10(9) cm(-2) appear to be realizable using the present selective MBE method. (C) 1999 Elsevier Science Ltd. All rights reserved.