Biasing

About: Biasing is a research topic. Over the lifetime, 29422 publications have been published within this topic receiving 301035 citations.

Electrostriction in Perovskite-Type Ferroelectric Ceramics

Abstract: The electrostriction and polarization in the perovskite-type ferroelectric ceramics have been calculated in the state under the arbitrary biasing field. Domain configurations produced by 180°-reversal or 90°-rotation have been represented here by the threshold angle θ180 or θ90; that is, domains, making smaller angles than θ180 or θ90 after the switching once occurs, are completely reoriented under the given bias. The electrostriction and polarization can be calculated as functions of θ90 and θ180, from the spontaneous strain and polarization of the crystal. The spontaneous strain in the rhombohedral crystal has been found as (3/2)[(π/2)-α] for the first time. Bias dependence of θ90 and θ180 have been obtained from the experimental results on the basis of the present calculations. Some discrepancies between the results and the expectation based on the activation field considerations are presumably due to the mechanical stress accompanied with 90°-rotations, and to the interaction of 180°-reversals and 90°-rotations.

Low-frequency noise properties of N-p-n AlGaAs/GaAs heterojunction bipolar transistors

Abstract: The low-frequency noise characteristics of N-p-n Al/sub x/Ga/sub 1-x/As/GaAs heterojunction bipolar transistors (HBTs) have been investigated as a function of bias current, device geometry, extrinsic-base-surface condition, Al mole fraction in the emitter, and temperature in order to identify the dominant noise mechanisms. These measurements show the existence of three distinct regions in the noise spectra: a 1/f noise line shape, a Lorentzian spectrum (noise 'bump'), and a white-noise region. The 1/f noise is attributed to fluctuations in the extrinsic-base surface recombination current. The noise bump is generated by an AlGaAs trap in the emitter-base junction. The DX center was identified as a possible candidate for this trap. It is shown that for 4- mu m*10- mu m emitter AlGaAs/GaAs HBTs, the use of a depleted, AlGaAs passivation ledge over the extrinsic-base surface typically reduced the 1/f base noise current by a factor of 10, and the reduction of the Al mole fraction from 0.3 to 0.2 decreased the magnitude of the noise bump by a factor of 3. >

Extended infrared photoresponse and gain in chalcogen-supersaturated silicon photodiodes

Abstract: Highly supersaturated solid solutions of selenium or sulfur in silicon were formed by ion implantation followed by nanosecond pulsed laser melting. n+p photodiodes fabricated from these materials exhibit gain (external quantum efficiency >3000%) at 12 V of reverse bias and substantial optoelectronic response to light of wavelengths as long as 1250 nm. The amount of gain and the strength of the extended response both decrease with decreasing magnitude of bias voltage, but >100% external quantum efficiency is observed even at 2 V of reverse bias. The behavior is inconsistent with our expectations for avalanche gain or photoconductive gain.

3D polysilicon diode with low contact resistance and method for forming same

Abstract: A semiconductor p-i-n diode and method for forming the same are described herein. In one aspect, a SiGe region is formed between a region doped to have one conductivity (either p+ or n+) and an electrical contact to the p-i-n diode. The SiGe region may serve to lower the contact resistance, which may increase the forward bias current. The doped region extends below the SiGe region such that it is between the SiGe region and an intrinsic region of the diode. The p-i-n diode may be formed from silicon. The doped region below the SiGe region may serve to keep the reverse bias current from increasing as result of the added SiGe region. In one embodiment, the SiGe is formed such that the forward bias current of an up-pointing p-i-n diode in a memory array substantially matches the forward bias current of a down-pointing p-i-n diode which may achieve better switching results when these diodes are used with the R/W material in a 3D memory array.