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Semiconductor Devices
Published in Dale R. Patrick, Stephen W. Fardo, Electricity and Electronics Fundamentals, 2020
Dale R. Patrick, Stephen W. Fardo
In an ordinary junction diode, the depletion region is an area which separates the P and N material on each side of the junction. This area develops when the junction is initially formed. It represents a unique part of the diode that is essentially void of current carriers. In this regard, the depletion region serves as a dielectric medium or insulator. When a diode has bias voltage applied, its depletion region will change in width. In a sense, this means that a diode responds as a voltage-variable capacitor. By definition, a capacitor is two or more conductors separated by an insulating material. The P and N materials, being semiconductors, are separated by a depletion region insulator. Devices designed to respond to the capacitance effect are called varactors, varicap diodes, or voltage-variable capacitors.
Analog Circuit Design
Published in Manoj Kumar Majumder, Vijay Rao Kumbhare, Aditya Japa, Brajesh Kumar Kaushik, Introduction to Microelectronics to Nanoelectronics, 2020
Manoj Kumar Majumder, Vijay Rao Kumbhare, Aditya Japa, Brajesh Kumar Kaushik
In general, we consider MOSFET where source and body terminals are tied together. If the bulk and source terminal voltages of a transistor differ from each other, body effect comes into the picture. To understand this, when VD = VS = 0, the VB becomes more negative that increases the charge density in the channel. Consequently, depletion region becomes wider and the threshold voltage increases. It can be shown that the threshold voltage is expressed in terms of source-to-body voltage as Vth=Vth0+γ(|2ϕF+VSB|−|2ϕF|)
Common Spectroscopic and Imaging Detection Techniques
Published in Helmut H. Telle, Ángel González Ureña, Laser Spectroscopy and Laser Imaging, 2018
Helmut H. Telle, Ángel González Ureña
As stated earlier, PDs in their simplest form constitute p–n junction devices, and in the majority of measurement configurations (at least small), reverse-bias voltages are applied. Across the p–n junction, a depletion region is generated, which separates the regions with (static) positively charged donor atoms in the n-type material from (static) negatively charged acceptor atoms in the p-type material. Mobile carriers move to their majority region under the influence of intrinsic or extrinsic (bias) electric fields. As a consequence, the width of the depletion region depends (1) on the doping concentrations and (2) on the magnitude of the applied reverse bias. In general, one finds that the lower the doping levels, the wider the depletion region.
Research on the Performance of Nuclear Battery with SiC-Schottky and GaN-PIN Structure
Published in Nuclear Technology, 2022
Shanxue Xi, Haijun Li, Linxiang Li, Kun Wu, Guangwei Huang, Zungang Wang, Yiyun Zhang, Chunzhi Zhou
The built-in electric field strength in the PN junction will affect the charge extraction efficiency, which is one of the most important factors to determine the output power of a nuclear battery. Therefore, increasing the doping efficiency of the P region will increase the built-in electric field strength and the extraction efficiency of ionization charges. The thickness of space-charge region is closely related to the doping concentration of the N region; the lower the doping concentration, the greater the thickness of the depletion layer. Hence, in order to obtain high open-circuit voltage, both sides of the PN junction should be heavily doped. However, the higher the doping concentration of the N region, the narrower the space-charge region, which will increase the recombination of carriers in the N region and reduce the short-circuit current. Therefore, the appropriate doping concentration in the N region can obtain better conversion efficiency. Figure 5 shows the relationship between the width of the depletion region and the doping concentration of the P and N regions. The width of depletion region W is inversely proportional to the doping concentration of the P and N regions. In order to improve the carrier collection rate and the output performance of the isotope battery, the width of depletion region W should be as large as possible within the range of beta particles.
Researches on the performance of GaN-PIN betavoltaic nuclear battery
Published in Radiation Effects and Defects in Solids, 2022
Shanxue Xi, Linxiang Li, Chunzhi Zhou, Haijun Li, Guangwei Huang, Kun Wu, Zungang Wang, Yiyun Zhang
The built-in electric field intensity in PN junction will affect the effective charge extraction, which is one of the most important factors to determine output power of nuclear battery. Therefore, increasing the doping efficiency of P region will increase the built-in electric field intensity and the extraction efficiency of ionisation charge. The thickness of space charge region is closely related to the doping concentration of N region, the lower the doping concentration, the greater the thickness of the depletion layer. Hence, to obtain high open-circuit voltage, both sides of PN junction should be heavily doped. However, the higher the doping concentration of the N region, the narrower the space charge region, which will increase the recombination of carriers in the N region and reduce the short-circuit current. Therefore, the appropriate doping concentration in N region can obtain better conversion efficiency. Figure 7 shows the relationship between the width of depletion region and the doping concentration of P and N regions. The width of depletion region W is inversely proportional to the doping concentration of P and N regions. In order to improve the carrier collection rate and the output performance of isotope battery, the width of depletion region w should be as large as possible within the range of radiation particles.
Impact of proton irradiation with different fluences on the characteristics of InP/InGaAs heterostructure
Published in Radiation Effects and Defects in Solids, 2019
Xiaohong Zhao, Hongliang Lu, Yuming Zhang, Yimen Zhang
The mechanism could be verified in Figure 5, which shows the plots of depletion region width and voltage with 3 MeV at different fluences. That is calculated form C–V plots measured under 5 MHz according to Equation (1) (10). In the low reverse bias, depletion region width is almost unchanged, which is due to that trap charges are enough to respond to the applied voltage change. When all traps participate in charging and discharging and the trap capacitance no longer changes, the depletion region width begins to widen, responding to the increasing absolute bias value. Under forward bias, the depletion region width slightly reduces with the increased voltage, which is attributed to the increased diffusion capacitance in forward bias. This is consistent with previous analysis.