Investigation of oxide precipitates in high resistivity silicon using light scattering tomography, low temperature photoluminescence, and deep level transient spectroscopy

Abstract

The formation and electrical activity of oxide precipitates were evaluated in p-type high-resistivity (HR) Czochralski (Cz) silicon (Si) wafers with varying interstitial oxygen concentrations [(Oi)] after high-temperature annealing. Using a combination of Light Scattering Tomography, Low Temperature Photoluminescence (LTPL) spectroscopy, and Deep Level Transient Spectroscopy (DLTS), we highlight the electrical signatures of oxide precipitates when they form in sufficient quantities to be detected. Meanwhile, the difficulty of growing oxide precipitates is confirmed in HR substrates with low oxygen content, which are safer for component integration. LTPL spectra confirm the activity of oxygen precipitates through D-band emissions across different [Oi] ranges. DLTS analysis of annealed samples with medium [Oi] enables the identification of deep level traps, notably at EV + 0.24 eV and EV + 0.42 eV, likely associated with oxygen precipitates and secondary defects. These findings will contribute to future strategies for the characterization of defects in industrial HR silicon substrates.