Questions tagged [semiconductors]
Most generally a class of materials that are neither insulators or conductors in their natural state, but which can be manipulated via doping or electric fields to change their conduction state. Silicon, Germanium, and GaAs are some usual materials. The term is also used to speak about devices that are made from such materials, for example, a processor from Intel can be called a semiconductor.
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Drift Current Concept in PN junction
In a PN junction, under no bias, when the depletion region forms an electric current is also formed in the direction from N side to P side. This electric field, also has a potential difference, ...
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Why is the Collector current of a BJT transistor independent of the Collector Base voltage?
Ignoring the modulation of the effective base width, why is the collector current independent of the reverse bias voltage across the Base-Collector P-N junction? On one hand, it is easy to see that ...
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Series connection of diode and resistor. Why is there a constant voltage across the diode?
So I know that a diode can be described using the Shockley equation and after a certain voltage, the diode current begins to increase rapidly. The nominal 0.7 volts. I also know that this voltage ...
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BJT NPN transistor
I am confused on a topic regarding NPN BJT transistors.
When there is a collector-emitter voltage (VCE) applied to the NPN transistor (as shown in the figure) without a emitter-base voltage (VBE), it ...
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Is it possible to determine the Miller voltage of a MOSFET from the ON-region characteristics?
Miller's voltage from \$I_{ds}\$ vs \$V_{ds}\$ characteristics for different values of gate-source voltages. Miller's voltage or Miller plateau is the critical gate-source voltage at which MOSFET ...
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How do you justify energy band bending in an unbiased MOS Capacitor?
Here is a MOS Capacitor:
(Image source: Chapter 5 of Modern Semiconductor Devices for Integrated Circuits by Dr. Chenming Hu)
Now lets consider the idea that the gate voltage is held at 0V, just like ...
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Carrier concentrations versus temperature and doping in Matlab
I am currently self studying structure of semi-conductors and I would like to make a graph in Matlab of the number of carriers as a function of temperature and doping. Let's say that I am testing ...
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Where is the flaw in this transistor, FET, Diode design?
I'm a hobbyist and I've designed and built (fabbed a small circuit board, schematic attached) a circuit to power a brushless DC motor using a solar panel which also charges a stand-by battery and ...
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Why does the Schottky barrier height remain constant?
If a metal and a semiconductor are connected, they are going to equilibrium. For this, the Fermi level has to be equal. So far I understood that this causes a charge exchange till said equilibrium has ...
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Diffusion Current for Non-Linear Charge Carrier Configurations
Diffusion current in a MOSFET device can be calculated using Fick's Law per \$J=-qD\frac{d \rho}{dx}\$. It is often taken that the charge carrier configuration (\$\rho\$) across the MOSFET channel is ...
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Understanding fabrication steps of creating TFT MOSFET from ZnO
A few days ago I found this paper about fabricating a thin film MOSFET using ZnO at low temperature.
It seems promising to me (to do at home, some people actually made their own MOSFET at home but ...
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What is a precise definiton of "cut-in" voltage as applied to diodes?
What is the "cut-in" voltage or knee voltage of a diode or transistor?
In a lot of books I read that the cut-in or knee voltage of a diode (or transistor) is when the diode starts conducting ...
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Conduction losses calculation of a SiC MOSFET
I have a question regarding conduction losses calculation of a SiC MOSFET. What I found in different research papers and in application notes is that you calculate the power dissipated during forward ...
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Formula for efficiency of half wave rectifier
I came across this formula for rectification efficiency of half wave rectifier:
η= (40.6 *resistance of load resistor )/ (resistance of load resistor+ resistance of secondary of transformer + ...
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Semiconductor device testing [closed]
I'm a graduate engineer who's recently started a job testing silicon wafers consisting of both power MOSFETs or diodes and some IGBTs.
Unfortunately there's little in terms of support and training ...
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