A new photoluminescence (PL) band in the energy range of $700\text{to}950\mathrm{meV}$ associated with hafnium implanted in silicon is reported. A shift in the position of photoluminescence peaks observed on the samples implanted with two different isotopes of Hf confirms the Hf-related origin of the observed photoluminescence band. Activation of the Hf-optical centers requires a $1000°\mathrm{C}$ anneal step. The intensity of the PL lines depends on the cooling conditions. The spectrum consists of 5 peaks in the rapidly quenched sample as opposed to 21 in the slowly cooled sample. Temperature- and excitation power-dependent PL measurements were performed to identify their nature. The $943.8\mathrm{meV}$ line was associated with an exciton complex, while the $896.6\mathrm{meV}$ line originates from impurity bound exciton. The $896.6\mathrm{meV}$ emission line appears to be related to a Hf-related deep level defect at $E_{\mathrm{C}}\text{−}0.22\mathrm{eV}$, the $845\mathrm{meV}$ line to a deep level defect at $E_{\mathrm{C}}\text{−}0.27\mathrm{eV}$. The pressure measurements indicate that the $845\mathrm{meV}$ peak could be an internal transition. It is also found that oxygen coimplantation enhances the PL intensity in rapidly quenched samples.

• Received 5 October 2004

DOI:https://doi.org/10.1103/PhysRevB.71.195208