Origin of Low-frequency Noise in Si n-MOSFET at Cryogenic Temperatures: The Effect of Interface Quality

• Published in: IEEE access Vol. 11; p. 1
• Main Authors: Oka, Hiroshi, Inaba, Takumi, Shitakata, Shunsuke, Kato, Kimihiko, Iizuka, Shota, Asai, Hidehiro, Fuketa, Hiroshi, Mori, Takahiro
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.01.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 1/f noise; Band tail states; Cryogenic temperature; Cryogenics; Field effect transistors; Fluctuations; Interface states; LF noise; Low-frequency 1/<italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">f noise; low-frequency 1/f noise; Low-frequency noise; Metal oxide semiconductors; MOSFET; MOSFETs; Quantum computer; Quantum computing; Qubit; Semiconductor devices; Si spin qubit; Silicon; Surface orientation; Temperature dependence; Temperature measurement
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2023.3327731

This study investigates the origin of low-frequency (LF) 1/ f noise in Si n-channel metal-oxide-semiconductor field-effect transistors (n-MOSFETs) under cryogenic operation. The fluctuation of the drain current increased with decreasing temperature, exhibiting LF 1/ f noise of more than two orders of magnitude higher at 2.5 K compared with that at 300 K. As revealed by the temperature dependence of the normalized current spectral density, the LF 1/ f noise at 2.5 K is primarily governed by carrier number fluctuations. To obtain insight into the carrier trapping centers under cryogenic operation, we investigate the effect of oxide/Si interface states on the LF 1/ f noise by utilizing Si n-MOSFETs with different surface orientations, i.e., different interface trap densities (D it ). The LF 1/ f noise is comparable between the surface orientations at 300 K, whereas excess noise was observed at 2.5 K for the surface orientation with higher D it in the order of (100)<(120)≤(110)-orientations. This indicates that the LF 1/ f noise at cryogenic temperatures originates from oxide/Si interface defects and disorders, that is, the interface states and band tail states. These states are localized at the conduction-band edge, which contributes to noise generation as the Fermi level approaches the conduction-band edge at cryogenic temperatures. This study demonstrates the significance of the oxide/Si interface quality in suppressing the LF 1/ f noise in Si MOS devices operated at cryogenic temperatures.