Superlattice Barrier of Epitaxial Silicon / Adsorbed Oxygen
Abstract
Lacking a suitable heterojunction, silicon has not played a significant role in quantum and ballistic devices as III-V compound semiconductors. We have succeeded in fabricating a short period superlattice consisting of silicon sandwiched between adsorbed oxygen. Specifically, several Langmuir of oxygen is adsorbed onto epitaxially grown silicon by MBE at relatively low substrate temperature, 450 - 500 C. Epitaxial growth may be continued provided before each subsequent deposition of silicon, a ten minute annealing is done at 600 C. For a structure consisting of 11 Åof silicon sandwiched between 1-3 Langmuir of adsorbed oxygen, a barrier height in excess of 0.5 eV is measured with I-V. In order to determine the barrier height, numerical calculation and simulation are carried out. The method involves comparing the derivative of the natural log of the current at some fixed applied voltage, with respect to (kT)-1, to the expression for thermionic emission. Another significant result is the lack of amorphous oxide/silicon interface defects usually manifested by the appearance of conductance peaks at low applied voltages.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1997
- Bibcode:
- 1997APS..MAR.C1808T