Increased thermal stability due to addition of Ge in B/Si(111) heterostructures

✍ Scribed by Douglas J. Tweet; Koichi Akimoto

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 799 KB
• Volume: 221
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(95)00928-0

✦ Synopsis

Of the numerous adatom-induced .v/3 surfaces, only Bv/3/Si(l 1 1) has the adatom in a substitutional site. Thus, research on Si/B/3/Si(1 1 1) has been motivated by the desire to create a new class of so-called 6-doped materials, in which holes produced by boron are trapped at the two-dimensional interface. Unfortunately, this structure degrades with low temperature annealing. However, the addition of Ge is expected to reduce the interracial strain and so improve thermal stability. Previously, we have used synchrotron radiation and anomalous X-ray diffraction techniques to determine ex situ the atomic structure of such a system. Here, using synchrotron radiation we have studied in situ heterostructures grown by molecular beam epitaxy and verified the improved stability. Specifically, we find that including Ge extends the annealing range by more than 100C without significant degradation. We have also successfully grown a heterostructure consisting of two Bw/3 layers separated by a 40 A spacer.