Variable-Temperature Noise Characterization of N-MOSFETs Using an In-Situ Broadband Amplifier

Abstract

Characterization of broadband noise of MOSFETs from room temperature down to 120 K in fine temperature steps is presented. A MOSFET is mounted on a reusable printed circuit board vehicle with a built-in low-noise amplifier, and the vehicle is loaded into a cryogenic chamber. The vehicle allows noise measurement in the frequency range from 50 kHz to 100 MHz. At low frequencies, it enables extraction of activation energies associated with electron trapping sites. At high frequencies, as has been suggested by noise figure measurements, the white noise of MOSFETs is shown to be dominated by the shot noise, which has much weaker temperature dependence than the thermal noise. The shot noise will be a problematic noise source in broadband RF CMOS circuits operating at cryogenic temperatures.

Variable-Temperature Broadband Noise Characterization of MOSFETs for Cryogenic Electronics: From Room Temperature down to 3 K

“…= 0.8 V with 𝑉 " = 0.1 V, and are 0.44, 0.36, and 0.29, respectively. The decrease in 𝐹 down to 4 K were observed, being consistent with the previous report [4].…”

“…As was reported experimentally in [4], MOSFETs ideally generate only thermal noise under a zero drain bias (𝑉 " = 0 V). Fig.…”

“…and 𝑉 " increase, 𝐹 decreases owing to barrier lowering at the source [9]. We found in the 𝑇 range from 300 to 120 K [4], that 𝐹 gradually decreased as 𝑇 decreased.…”

“…= 180 nm will be presented in this paper. The system configuration is similar to that in [3,4], except that an external auxiliary amplifier is used for reducing the power consumption of the main board.…”

“…7 are thermal noise 𝑆 *+ (green), full-shot noise 2𝑞𝐼 " (orange), and the sum of these (blue). 𝑆 *+ intersects 2𝑞𝐼 " at 𝑉 ",-./00 = 2𝑘 $ 𝑇/𝑞 [4], indicating that thermal noise dominates under low 𝑉 " (< 2𝑘 $ 𝑇/𝑞) and shot noise becomes dominant otherwise. The values of 𝑉 ",-./00 at 𝑇 = 300, 100, and 5 K are 52, 17, and 0.8 mV, respectively.…”