We report on a photoluminescence (PL) study of silicon subjected to reactive ion etching (RIE) using a mixture of helium and hydrogen-bromide as a plasma. Several luminescence lines, some of which, such as the W- (1018 meV), X- (1040 meV), and T- (935 meV) lines, are known from defects produced by high-energy irradiation, manifest damage of the crystalline material. Two broad PL lines are observed at 1020 and 958.6 meV with intensities dependent on the phosphorus concentration in the samples. These lines are absent in boron-doped material. Furthermore, the introduction of these lines depends on the specific plasma used in the RIE treatment. The dependencies on excitation power and temperature of these lines are investigated together with the effects of subsequent annealing. The two lines are ascribed to the no-phonon line and the transverse optical phonon replica of an exciton bound at a complex defect, probably involving intrinsic point defects and/or atoms from the etch plasma. Other PL lines at 1008 and 997 meV emerged on the samples upon annealing at 400°C.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry