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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What exactly happens at the fundamental level if base voltage is higher than collector voltage in CE transistor?
In the first answer to this question, it is stated that:
This happens even if the base and collector are at the same voltage (!). Basically, one way to model a transistor is as the base-emitter diode,...
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How do you make M2 Ultra with lithography?
The M2 Ultra chip is unusual not because it's a single chip made of two halves, but because the halves are centrosymmetric images of each other instead of translation. Assuming the wafer is exposed ...
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Why aren't inverters used in a half adder made of NOR gates?
That's schematic of half adder using only NOR gates.
Why aren'y inverters used?
In the picture, there are 2 NOR gates where the two inputs are same as A or B.
Why don't we replace these with a NOT ...
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I want to make use of an Allegro A1324LUA-T Hall sensor to sense a very small magnetic field change. Would it be possible?
I am looking into using an Allegro A1324LUA-T for sensing very small magnetic field changes.
The data sheet shows that the sensor gives a 5mV/G change in voltage so I can sense a 0.1 Gauss change if I ...
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Understanding the formula of the saturation current in a PN-junction diode
According to Wikipedia, the saturation current in a diode is given by the following formula:
$$I_S = qAn_i^2\left(\frac{1}{N_D}\sqrt{\frac{D_p}{\tau_p}} + \frac{1}{N_A}\sqrt{\frac{D_n}{\tau_n}}\right)$...
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How to calculate the creepage distance of a package through package outline?
How do I calculate the creepage distance of a package which is not specified by the manufacturer?
By looking at the drawing of the package, could I calculate it? If yes then how?
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Multiple Source Terminals of SiC MOSFET
I want to know that most of the semiconductor top side cooled package have more than one power source terminal. I can understand by doing so you can minimze the loop inductance of gate driver loop ...
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How can I make a load inductor for a double pulse test?
How can I make a load inductor in the lab with value of roughly 115 uH for the sake of a double pulse test measurement? Do I need an LC meter to do that?
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Origin of the term "doping" in semiconductors
Is there a known origin/etymology for using the terms "doping" and "dopants" when describing the process of introducing impurities to semiconductors? I have never been able to find ...
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LED limit to short pulse and high power
I’m studying the viability of a small footprint distance detector that relies on a LED, a photodetector and some lenses. It’s meant for a distance above 150m, where the light beam travel time is ...
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Why does the width of the depletion region decrease with the increase in doping concentration?
Should the depletion region be increasing in width as more and more ions are uncovered at the junction due to the diffusion of majority carriers from one side of the junction to the other? Then why ...
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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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Movement of electrons and not holes in a PN junction?
So I've been clearing my concepts about the PN junction upto a deeper level today, and I've got a few questions to ask and clarify my concepts:
In a pn junction, due to diffusion, Only the electrons ...
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An accurate representation of the movement of holes in a PN junction
I want to clear my conception of the depletion region in an unbiased PN junction.
Before the formation of a depletion region in a PN junction, in the P region there is an excess of holes, aka places ...
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Contribution of hole diffusion current and electron diffusion current in a pn junction
I have recently got to learn that the hole diffusion current and electron diffusion current both point towards the N side in a PN junction? And the diffusion current is hence towards the N side.
And ...
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Drift Current in PN Junction and Barrier Voltage
I am reading this book, but the idea presented by it is very unclear.
It quotes:
However, I am not entirely convinced with the reason it provides here, like why are the minority carriers that reach ...
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Electric potential in a PN junction and the direction of electric field
Why is the direction of the electric field from N to P? Is it a standard convention?
Why are the directions of the drift current Is and diffusion current Id in their respective directions? In my book, ...
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Why is diffusion current due to p side in a diode inversely proportional to doping concentration of p side in the case of forward bias?
In a diode at equilibrium, there are Pn holes on the n side of the junction. These are maintained by the dynamic equilibrium of diffusion due to holes = drift due to holes. When a forward bias 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 happens to a PN junction diode and its depletion width if forward bias voltage is greater than built-in voltage?
If the forward bias voltage applied to a PN junction diode is greater than the built-in voltage, what will happen? Will there be any depletion region? If a depletion region is still there, what will ...
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What happens when two same type semiconductiors are joined togehther?
If we join two n-type semiconductors with different doping concentrations (for example doping concentrations are 4x10^15 and 10^15 per cubic centimeter), what will happen? Will there be a depletion ...
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How can I reduce the output voltage in a simple way?
I want to connect my old smartphone (Galaxy S4) directly to a charger without battery.
I want to connect plus and minus pins, so I need 3.8 V input, but the charger gives 5 V.
What is the best and ...
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How can I clip a voltage upper limit in an analog signal?
This is a theoretical question since I've come across this type of problem many times.
Suppose an amplifier is powered between 12 V and -12 V, so the signal output can reach a maximum of 12V. If I am ...
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Are semiconductors (specifically silicon) the only materials that can be used for making image sensors in digital cameras?
Could no other type of materials be used even if it means an entirely different sensor design or layout?
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Why doesn't a diode pass current when reverse biased?
If one tacks a P-type semiconductor to an N-type semiconductor, a P-N junction forms in which electrons diffuse from the N-type to the P-type causing a diffusion current. Some time passes, and an ...
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Influence of gate resistors and capacitors on driving gate of mosfet
Good Day,
I wannted to ask in a typical gate driving circut of a Mosfet, we always have Rgoff, Rgon,RGS and CGS as shown in below screenschot. What is the purpose of these components in driving the ...
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Fermi levels in PN-junction under forward bias are not constant throughout each side
This is, in a way, a follow-up to this question.
I see the following band diagram for a forward biased diode everywhere:
In the above picture, I marked a point with potential zero (where battery is ...
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Mass action law in semiconductors
In thermal equilibrium, the mass action law states that $$n_{h}n_{e}=n_{i}^{2},$$
where \$n_{h}\$ is the equilibrium concentration of holes and which equals to the equilibrium concentration of ...
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Resistance depending on voltage - the chicken and the egg?
If I understand correctly:
The resistance of some circuit components (like diodes) depends on the voltage across them.
When two components are connected in series: \$\frac{V1}{V2} = \frac{R1}{R2}\$
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What is equilibrium carrier concentration in a semiconductor? Is it material specific? How to calculate it?
Is equilibrium carrier concentration dependent on doping density? If it is, then how to know how much the doping density should be for a particular semiconductor device?
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