ON-WAFER LOW FREQUENCY NOISE INVESTIGATION OF THE 0.35 µ µ µ µm n AND p TYPE MOSFETS, DEPENDENCE UPON THE GATE GEOMETRY (original) (raw)

Low frequency noise of p and n type MOSFETs were investigated. Flicker noise was found dominating in the spectra of MOSFETs low frequency fluctuations. Simulations were performed using both models associated with mobility fluctuations and trapping of current. Good fit of the simulated to the measured noise data enabled an extraction of the effective density of the interface states, the spectral density of the flat band voltage fluctuations and Hooge parameter α α α αH H H H. For n type MOSFETs grown on the same wafer the flicker noise was found to be one order of magnitude higher than that for the p type devices.

Analysis of Drain Bias Dependence of 1/f Noise in HV-MOSFETs

The behavior and dependence of 1/f noise versus drain bias in high-voltage (HV-)MOSFETs is examined in this paper. Low frequency noise of 50V N-and P-channel HV-MOSFETs was measured over a large range of gate and drain bias conditions. Drain voltage steps were chosen very small in linear region while enough points were also measured in saturation regime up to 20V. Recent work on characterization and modelling on flicker noise of HV devices proved that while the overall noise is mostly dominated by the noise originating in the channel, the drift-region-generated noise is apparent only in linear operation especially in strong inversion region of long channel devices. In order this to be clear, this work focuses on the behavior of flicker noise vs. drain bias for all inversion regime.

Low-Frequency Noise in MOSFETs

—As soon as inherent noise of MOSFET becomes an issue in the design of ICs, accurate physics-based models are necessary. The present paper reviews the different noise sources responsible for MOSFET drain current fluctuation. The long-running question of the physical origin of 1/f noise is briefly addressed. Special attention is paid to the Random Telegraph Noise (RTN) since it gets as significant as statistical variability in deeply-scaled CMOS technologies. Due to the extreme complexity of the underlying physical mechanism, which is capture and emission of carrier by an oxide defect, we adopt a phenomenological approach. A stochastic model is firstly derived. Then, the fundamental physical parameters are discussed based on the simple Shockley-Read-Hall theory and the charge sheet approximation.

Evaluation of Low-Frequency Noise in MOSFETs Used as a Key Component in Semiconductor Memory Devices

Electronics

Methods for evaluating low-frequency noise, such as 1/f noise and random telegraph noise, and evaluation results are described. Variability and fluctuation are critical in miniaturized semiconductor devices because signal voltage must be reduced in such devices. Especially, the signal voltage in multi-bit memories must be small. One of the most serious issues in metal-oxide-semiconductor field-effect-transistors (MOSFETs) is low-frequency noise, which occurs when the signal current flows at the interface of different materials, such as SiO2/Si. Variability of low-frequency noise increases with MOSFET shrinkage. To assess the effect of this noise on MOSFETs, we must first understand their characteristics statistically, and then, sufficient samples must be accurately evaluated in a short period. This study compares statistical evaluation methods of low-frequency noise to the trend of conventional evaluation methods, and this study’s findings are presented.

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