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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Why should VS always be larger than VIH? [closed]
Why is VS always larger than VIH? What are possible issues?
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How can you measure voltage differences less than thermal voltage (~26mV at room temp)?
If thermal voltage is the average voltage of any given electron relative to the voltage at ground state, and this presumably fluctuates, how can you make any measurement on a circuit more accurate ...
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Two diodes connected in opposed way show different results (simulation vs physical circuit vs simulation)
I am confused about this circuit found in Electronic Devices and Circuit Theory By Robert Boylestad 10th Ed.
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I don't understand why D1 (left diode) has a Vd1 = 0v in equivalent circuit:
When I ...
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What kind of PLL is typically used for the digital logic in high-frequency ASIC's? [closed]
Want to generate clocks up-to 2GHz from the PLL internal to the ASIC for the critical data-path logic, please advise. Thanks!
Looks like there are wide variety of PLL's, dithered, multiphase, Fs, etc. ...
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What does "strobe" mean in the context of semiconductors?
I was reading the data sheet for SN7425, and it calls the semiconductor a "Dual 4-Input NOR Gates With Strobe"
What does it mean by "Strobe"? Does it affect input/output?
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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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What is / how do I find the general ratios of all of the materials used in a cmos chip?
I am doing a life cycle assessment of a CMOS chip. But I am struggling a lot in finding the general ratios or quantities of the materials used in a chip, which is necessary for calculation of ...
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How to conduct temperature variant EM simulations in HFSS?
I want to conduct temperature variant EM simulations in HFSS i.e. simulate s parameters of a CPW at various temperatures. I am using a temperature variant material using thermal modifiers. I have also ...
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A problem from shift in the fermi energy level
if the effective mass of holes in a semiconductor is 5 times that of the electron, at what temperature would the fermi level shift by 15% from the middle of the forbidden energy band? (given that, eg =...
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A problem regarding shift in the Fermi energy level [duplicate]
The effective mass of holes in a semiconductor is 5 times that of the electron, at what temperature would the Fermi level shift by 15 % from the middle of the forbidden energy band (given that, eg = 1....
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Adapter for a function generator output
I want to order this adapter, but I can't find it on the web. Can anyone please confirm the exact name of this adapter for a function generator having a channel output and terminals for a DC power ...
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Simple circuit to bypass preamp when battery fails
A guitar has an on-board battery powered pre-amp between the pickups and the output jack. This is great until the battery fails, when it goes dead until the battery is replaced.
I would like to have a ...
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Jump on varistor I/V curve when "passing" through max. leakage current region to max. clamping voltage region?
I'm taking a course on semiconductor physics and another on something like "usage of electronic devices". On both I've come across the I/V curve on a varistor, this is:
I cannot find the ...
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Noise in classical quantum transmission
In classical quantum transmission, we introduced a scattering model that includes two components: free projection and collision
Now, in this figure, this model is introduced that when it goes up in ...
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BJT transistor working and construction
Why is electron concentration zero at collector side of the base in BJT transistor? And if electron concentration decreases with distance and becomes zero at the end base region how can it produce ...
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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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MOSFET switching on
I have a doubt. Consider an N-MOSFET: which is the voltage that can switch on it? The voltage between Gate and? Sometimes I read "between Gate and Bulk", sometimes "between Gate and Source", sometimes ...
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Two semiconductor physics problems with similar data but different solution methods
Prob 1: Find the conductivity of n-type Ge at room temperature. Assuming one donor atom in each 108 atoms. The density of Ge is 5.32 x 103 kg/m3 and the atomic weight is 72.66 kg/k-mol. Given e=1.6 x ...
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Electron holes and negatively charged particles [closed]
I'm studying BJTs and have a kind of legacy question. Is there any relation with electron holes and the positive charged point charges you'd see in simple Coulomb law applications?
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How to calculate the diffusion length in modulation doping?
I have read a paper about an application of modulation doping in bulk thermoelectric materials. In this paper, the nanoparticles diffuse carriers into the host materials, and I want to estimate the ...
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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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Orientaion Flat on Semiconductor Wafer
On semiconductor wafers there is a straight line, which is called Orientation Flat.
What exactly are these and how they are formed?
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What is the reason why thermal aging affects only the Cds capacitance but not the Cgs or Cgd capacitances?
Please take a look at the following images, experimentally obtained from a power cycling test of a power MOSFET. After the test where thermal aging is created due to repetitive power cycles, it is ...
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How does one manufacture a P-N junction?
When I read a physics textbook about a P-N junction, it will tell me that you connect a P-doped semiconductor to an N-doped semiconductor, and you form a depletion region.
From what I know about ...
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Bipolar Junction Transistor operating modes
If I use a BJT transistor as a switch, the transistor operates in the saturation or cut-off region, not in the active region.
However, some sources use the formula IC = β·IB. However, this formula is ...
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Why are microprocessors made using silicon and not germanium? [closed]
I heard that microprocessors are usually made using silicon, yet germanium has a better conductive state.
Why isn't germanium not chosen instead, taking to account that better conductors provide ...
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Calculate the absolute value difference in work function for two diodes
Given two semiconductor diodes where one is silicon and the other is called Graham, and both are connected by ideal wires that do not affect their work functions, and they are also in thermal ...
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Who is the manufacturer of the Y31 5133 mic?
My question is in this PCBA I need the information of the who is the manufacturers of the mic the full details of that mic...
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Can a thyristor regain its forward/reverse blocking capability if the current through it is "instantly" brought to zero?
I am imagining a situation where we have several series-connected thyristors, say 10, each that can block a voltage of 100V. So, the ten series-connected thyristors together can block a total voltage ...
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Can I measure the internal termination resistance of a MIPI receiver?
This question is further to: How accurate are internal terminators on chips with high speed differential inputs?.
I would like to measure the actual termination resistance inside one of these chips (...
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How accurate are internal terminators on chips with high speed differential inputs?
I'm aware that due to process variation, some analog parameters of semiconductor devices can vary; sometimes quite a lot. (E.g. the SST3904 transistor specifies a DC current gain somewhere between 100 ...
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Process compatibility between a non-planar avalanche photodiode and planar CMOS at 0.130μm process technology node
I plan to integrate a non-planar P⁺⁺/i/P⁺/N⁺⁺ avalanche photodiode (APD) array with a peripheral control circuit (e.g., trans-impedance amplifier, analog-to-digital converter, and quenching circuit) ...
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Purpose of Schottky diode in this schematic
I have come across the power supply management section used in the Verdin Development Board, addressing overvoltage, undervoltage, overcurrent, and reverse voltage protection.
While I understand how ...
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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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Why is the common emitter input insensitive to base width modulation?
According to Robert F. Pierret (1996) in page 411 of the 2nd edition of the textbook Semiconductor Device Fundamentals, common emitter input of PNP BJTs is insensitive to base width modulation. Isn't ...
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Why does light doping imply a large temperature coefficient?
In a discussion about how one can make integrated resistors in a given IC technology, Gray, Hurst, Lewis, and Meyer (Analysis and Design of Analog Integrated Circuits) remark that if we want to use a ...
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