26th Australian Institute of Physics Congress and the Australian and New Zealand Conference on Optics and Photonics

Photo-Induced Current Transient Spectroscopy of Defects in Ion Implanted High-Resistivity Silicon

Not scheduled

1h 30m

Belinda Hutchinson Building (The University of Sydney )

Contributed Oral COMMAD - Optoelectronic and Microelectronic Materials and Devices Parallel sessions

Description

Photoinduced Current Transient Spectroscopy (PICTS) is a technique developed to identify electrically-active charge traps in high-resistivity epitaxial substrates, where conventional capacitance-based methods are ineffective. [1] The ability to probe high-resistivity materials makes PICTS well-suited to the characterisation of silicon materials for quantum device applications. High-resistivity substrates are typically necessary for fabrication of spin-based silicon quantum computing devices. [2] To study defect states in such substrates, we perform photo-induced current transient spectroscopy (PICTS) on simple source–drain devices implanted with low fluences of Er, and H ions. Measurements were carried out using a 780 nm laser diode over a temperature range from 86 K to 300 K. PICTS probes photo-conductivity decay as a function of temperature, revealing generation–recombination processes in highly resistive semiconductors. This non-invasive technique has high sensitivity to oxide and bulk defects and only requires two diffused or ion implanted ohmic contacts to the layer under investigation. As an optically driven technique, PICTS can probe defects at cryogenic temperatures below 4K with photon pulses being used to excited charge carriers across the bandgap to circumvent the carrier freeze-out that occurs at these low temperatures. [3] We present the defect signatures of Er and H implanted samples, examined both as implanted and after annealing at 200°C and 300°C, respectively. These results enable correlation between specific impurities and electrically active defects relevant to semiconductor and quantum devices.

[1] J. C. Balland, “Investigation of deep levels in high-resistivity bulk materials by photo-induced current transient spectroscopy,” J. Phys. D: Appl. Phys., 19, no. 1, pp. 57–70 (1986).
[2] S. R. Schofield et al., “Roadmap on atomic-scale semiconductor devices,” Nano Futures 9, 012001, (2025).
[3] A. Erol and M. Ç. Arıkan, “Photoconductivity and transient spectroscopy,” in Semiconductor Research, Springer Series in Materials Science, vol. 150, pp. 333–365 (2012).