Radiation Effects on the $1/f$ Noise of Field-Oxide Field Effect Transistors

Abstract

Low-frequency (1 ) noise measurements were performed at room temperature as a function of gate bias on Field-Oxide Field Effect Transistors (FOXFETs) that were irradiated with 10-keV X-rays and then annealed at room temperature. The resulting oxide-trap and interface-trap charge densities were estimated by the midgap charge separation technique. Some devices also were exposed to 85% relative humidity at 130 C for three days after irradiation and annealing. Effective border trap densities were estimated from noise measurements in each case. The noise magnitude increases after irradiation and decreases first during annealing and then even more significantly after moisture exposure. The post-humidity-exposure noise for the irradiated devices is well below the pre-irradiation noise for these devices and experimental conditions. The increased noise due to irradiation is attributed to O vacancies and hydrogen bridge (Si-H-Si) defects in the near-interfacial field oxide. The reduction in noise with room-temperature annealing and humidity exposure is due to a combination of thermal and tunnel annealing processes and defect passivation reactions involving water.

Comparison of Charge Pumping and <formula formulatype="inline"> <tex Notation="TeX">$1/f$</tex> </formula> Noise in Irradiated Ge pMOSFETs

“…Excess drain-voltage noise power spectral density as a function of frequency at and , before and after total dose irradiation and 10-hour annealing, for . the noise processes, is estimated to be , to be consistent with previous work [5], [12]- [15], [29], [31].…”

“…Low frequency noise measurements were used to estimate border trap densities in these devices [5], [12]- [15], before and after irradiation, and after biased annealing. During the measurements, the devices were operated in strong inversion in the linear region, with the gate-to-threshold voltage difference , and 100 mV applied to the drain, while all other pins were grounded (unless stated otherwise).…”

<formula formulatype="inline"><tex Notation="TeX">$1/f$</tex></formula> Noise and Defects in Microelectronic Materials and Devices

“…22, a pre-requisite for a defect to contribute to the measured noise is that one charge state of the defect lie above the Fermi level, and another lie below it. With the assistance of thermally assisted defect reconfiguration, a change in charge state can occur even if each energy level is more than a few above or below the Fermi level [10], [143], in contrast with the (simplifying) assumptions of the number fluctuation model in original form.…”

Comparison of a 65 nm CMOS Ring- and LC-Oscillator Based PLL in Terms of TID and SEU Sensitivity

“…These circuits are commonly used in high-energy physics experiments such as CMS or ATLAS, in sensor interfaces and readout links. However, those environments can contain high amounts of ionizing radiation that degrade the silicon transistors' operation, resulting in a reduced performance and increased system noise [3] [4]. Not only does the performance of the circuit typically degenerate due to mismatch [5] and reduced drive strength, also high-energy particles create upsets and transients in circuits where triplication is sometimes difficult to enforce [6] [7].…”