UBC Theses and Dissertations
A study of the condensed phase in phosphorus doped silicon Halliwell, Robin Ernest
Photoluminescent studies give evidence that a condensed phase of electrons and holes can be formed in silicon containing phosphorus donor concentrations from 9.0 x 10¹⁵ cm⁻³ to 4.3 x 10¹⁹ cm⁻³. When the impurity concentration is less than that required for derealization of the donor electrons, the condensed phase takes the form of electron-hole drops with carrier concentrations of 3.0 x 10¹⁸cm⁻³. For Impurity concentrations greater than that required for derealization of the donor electrons the experimental observations are interpreted as evidence for a condensed phase involving only holes. Heat treatment of silicon doped with phosphorus is found to produce marked changes in both the photoluminescence and the electron paramagnetic resonance for samples containing impurity concentrations 2.2 x 10¹⁸cm⁻³ ≤ N[sub D] ≤ 1.3 x 10¹⁹ cm⁻³. These changes are interpreted in terms of the production of neutral traps by residual impurities such as carbon and oxygen. The effect of this heat treatment on the photo-luminescence lends support to the hypothesis of a condensed hole phase for high impurity concentrations.
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