Wagga2026/AC2MP2026

Photo-Induced Current Transient Spectroscopy of Si/SiO₂ Interface Defects in High-Resistivity Silicon

Not scheduled

20m

Convention Centre (Charles Sturt University, Wagga Wagga NSW Australia)

Poster Microstructural characterisation Microstructural characterisation

Speaker

Ms Awsaf AlSulami (University of Melbourne)

Description

Silicon metal-oxide semiconductor (MOS) device structures are vital for realizing quantum computing devices based on single atoms acting as qubits in silicon. These atoms must be located within ~20 nm of the Si/SiO2 interface to allow proper operation of control electrodes and read-out structures. [1] Qubits store quantum information in electron–nuclear spin states, which are highly sensitive to fluctuating electric and magnetic fields arising from nearby charge and spin defects. Therefore, probing the Si/SiO2 interface quality is crucial, as environmental interactions can induce decoherence. High-resistivity silicon substrates are essential for quantum applications because they minimize parasitic conduction and electromagnetic losses [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, H, and P ions. Measurements were carried out using a 780 nm laser diode over a temperature range from 300 K down to 86 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 ohmic contacts diffused through a layer. 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]

[1] A. Chatterjee et al., “Semiconductor qubits in practice,” Nat. Rev. Phys. 3, 157–177 (2021).

[2] M. Checchin et al., “Low-temperature loss tangent of high-resistivity silicon using a high-Q superconducting resonator,” Phys. Rev. Appl. 18, 034013 (2022).

[3] A. Erol and M. Ç. Arıkan, “Photoconductivity and transient spectroscopy,” in Semiconductor Research, Springer Series in Materials Science 150, 333–365 (2012).