Defects in High-Mobility Semiconductor Systems and Other Low-Dimensional Heterostructures

摘要

Experimental work funded under the subject contract was completed at the University of Lund during the period 23 Dec 1987 - 23 April 1988. The observed findings have now been assessed and interpreted, and the results are presented here in 3 parts. Part I describes research on the Pb center of oxidized silicon surfaces. This center provided an important test defect for inauguration of a new opto-electronic measurement system which was assembled at Fort Monmouth as part of the planned research. The Pb center is the most important defect in MOS integrated circuit technology. In addition to being of much interest in itself, it provides an excellent probe to test interface interactions with current carrier holes and elections, and with overlying layers of other semiconductors or superconductors. The optical absorption thresholds of this center were determined by the initial slope method, and compared with electrical energies to yield the Franck-Condon configurational change--found to be in good accord with molecular orbital theory. The parameters measured here will be of direct application in study of high-Tc superconductor interactions with silicon substrates. Part II describes similar measurements on defects in GaAs. Defects in this compound semiconductor are much more difficult to characterize, primarily because the best technology--electron spin resonance--is not so widely applicable as in Si; thus the electrical data cannot be clearly associated with specific point defect structures. Sweden. (rh)