Effects of uniaxial stress on the electronic state of the hydrogen-carbon complex in silicon

We applied deep-level transient spectroscopy (DLTS) under uniaxial stress t o study the structure and bonding character of a hydrogen-carbon complex. T he application of (1 1 1) and (1 1 0) compressive stresses split the DLTS p eak into two as intensity ratios of 1:3 and 2:2, respectively, which were t he ratios of the low-temperature peak to the high-temperature peak. No spli tting was observed under the (1 0 0) stress. These results indicate the tri gonal symmetry of the complex and the antibonding character of its electron ic state, and are consistent with the previously proposed atomic model of t he complex, in which the hydrogen atom occupies the bond-centered site betw een silicon and carbon atoms. Furthermore, under the (1 1 1) stress, we obs erved that the energy of the electronic state corresponding to the low-temp erature DLTS peak increased linearly with stress by 23 +/- 5 meV/GPa while that of the high-temperature peak only slightly decreased with stress by 6 +/- 5 meV/GPa. Under the (1 1 0) stress, the energy of the electronic state of the low-temperature peak had almost no stress dependency and that of th e high-temperature peak decreased linearly with stress by 15 +/- 5 meV/GPa. Based on the above atomic model, we can consistently understand the opposi te stress dependencies under (1 1 1) and (1 1 0) compressive stresses, cons idering the atomic displacement of the H-C complex under the stress. (C) 20 01 Published by Elsevier Science B.V.