Questions tagged [solid-state-devices]

Refers to solid devices built on silicon wafers or ceramic substrate. Materials used could be silicon, germanium or gallium arsenide with copper conductors and oxide based insulators. Doping is the addition of performance enhancements compounds such as gold or germanium. Includes transistors of all types and logic, analog and special purpose devices such as CCD sensors. When done devices are sealed with plastic or ceramic compounds.

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20 views

Short Channel MOSFET model

I was reading on a book (Thomas Lee, The Design of CMOS Radio Frequency Integrated Circuits) that in a short channel model, since the phenomenon of drift speed saturation is very relevant, it is a ...
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33 views

Why is the absorption coefficient (α) not zero for energy of incident photon less than the band gap of the semiconductor?

α ( Absorption Coefficient) tells us about the absorption of a photon by a semiconductor for the creation of electron-hole pairs. The absorption coefficient increases abnormally as the energy of ...
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55 views

What is the scope of semiconductor device fabrication compared to other fields? [closed]

I am planning on applying to colleges for pursuing an MS degree. I would like to know the scope of semiconductor device modelling, both in terms of jobs as well as research. I also wish to know about ...
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How does a FinFET reduce subthreshold swing comparing to a regular MOSFET?

I get that a lower subthreshold swing means there is a smaller current when the transistor is off and that's one of the reasons that finFET is preffered to MOSFET. But I don't understand how it does ...
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Why datecode is SO IMPORTANT to chip manufacturers?

With the miniaturization of the devices, chip marking has shrunk, not only in size, but also in content. And while the part number got compressed to as little as two letters (or in some cases ...
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1answer
29 views

Thermal generation of electron-hole couples and reverse biasing

I'm studying the PN junction and I have some problems figuring out thermal generation of couples electron-hole in reverse biasing. The analysis is the standard one (for example, one can find it in the ...
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89 views

Circuit simulator for a musical tesla coil?

I want to make a musical tesla coil. But I want to do some experimenting with the values of the voltage, turns ratio and the audio input. So I need a circuit simulator so that I can fixate on what ...
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2answers
143 views

BJT: why does Ic increase when temperature increases? [closed]

When the temperature of an BJT increases, the thermal voltage $$ V_T = \frac{k_BT}{q} $$ where \$k_B\$ is the Boltzmann constant, \$T\$ is the absolute temperature of the junction, \$q\$ is the ...
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2answers
51 views

On what inherent parameters does the speed of mosfet depend in a SRAM cell circuit?

I want to design 3D IC with 2 stages for a simple SRAM cell. Some of the MOSFETs will be on the top stage while some on the bottom stage. The MOSFETs on the top stage are supposed to be degraded in ...
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1answer
161 views

So why do SSD disks have a reputation for power efficiency?

Why do SSD disks have a reputation for power efficiency? I've just looked at some the spec sheets for SSD and mechanical hard disks. In a lot of cases, the even during idle state, SSDs use slightly ...
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82 views

High frequency switching applications

I was reading that for high frequency switching applications with semiconductors, the ratio of the electron to hole mobility should be high. Why is it so? Is it a necessary condition always? Or ...
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2answers
212 views

How do phosporus atoms affect the conductivity of a doped semiconductor?

Free electrons come from electrons in the Phosphorus atom when it excites to the conduction band. This leave an ion, what effect does this positive ion have on the flow of electrons?
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49 views

Enhancement type MOSFET - channel formation

In an enhancement type MOSFET (an n channel one assumed here), when a positive gate to source voltage is applied, the holes of the substrate near the gate move deeper into the substrate away from the ...
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1answer
108 views

Question on MOSFET - small signal model

In the small signal model of a MOSFET, the current from the drain to the source (for an n channel MOSFET) is a function of the gate to source voltage only. But, if a positive voltage was not applied ...
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3answers
179 views

Why do tube amplifiers have such (relatively) small reservior capacitors?

In learning about guitar amps, I've been studying the schematics for solid state and tube amplifiers, and I found a pattern that I've never seen an explanation for. If you consider any of the main ...
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1answer
50 views

Three-wire Control

Is it true that the three-wire control identifies the number of wires between the contactor and the control push buttons? I have been looking through the entire book, but can't seem to find a concise ...
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2answers
89 views

Why conductivity increases in semiconductor when doped?

I know it depends upon the concentration of electrons and holes . So if we add donor atoms, even though electron concentration in conduction band increases , hole concentration decreases due to more ...
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1answer
45 views

Why in semiconductor studies, we are only concerned with reduced zone representation of e-k diagram?

Does electron transition from conduction band to valence band takes place only in first Brillouin zone? Or can it happen in any other Brillouin zone?
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85 views

Why carriers move when Electric field is applied on Haynes-Shockley experiment

I would like to know why excess carriers/minority move when an electric field is applied at the Haynes-Shockley expirement
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1answer
210 views

Confusing regarding measuring barrier potential of a pn junction using a voltmeter

I have been trying to understand why we can't measure the Barrier potential existing in an unbiased pn diode but on seeing the answers I am quite confused. There seems to be two answers to this ...
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1answer
66 views

on-state voltage

I am trying to study an ever-on IGBT. in other words, IGBT is tried to be on in a long time. To this purpose, a +15V constant dc voltage is applied to the gate-emitter. But, when connecting a +2V ...
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1answer
58 views

General classifications of amplifiers

Some general classifications of amplifiers are wrote down below. Voltage Amplifier -> Voltage-Controlled-Voltage Source -> Device: OP AMP Current Amplifier -> Current-Controlled-Current-Source -> ...
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1answer
101 views

MOS Capacitor Band Edges

I am trying to understand the MOS-Capacitor band edge shapes. When negative voltage is applied for gate, why does the band edge across the insulator shift upward (and linear decreasing band edge)? ...
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2answers
70 views

semiconductor equilibrium and steady state

Why should equilibrium imply steady state? For example, there is a process whose rate increases with time and this process can be exactly balanced by an inverse process whose rate also increases with ...
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1answer
67 views

What is the maximum output current for a practical operational amplifier? [closed]

We have been given a table of electrical characteristics containing the values for the ideal and practical values of operational amplifiers but it does not include the maximum output current. What is ...
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1answer
113 views

Electrons and Holes in a semiconductor

In an exercise I have an un-doped silicon I find that p=1.80e+11 ,n=6.60e+10 , should the numbers be more close to each other? (for example in GaAs I find 1.10e+14 and 1.60e+14)?? (also p number of ...
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1answer
778 views

Applying KVL on PNP Voltage Divider Bias BJT

The circuit above is a PNP Voltage Divider Bias BJT. From the book, to get the emitter current, the circuit was transformed first into a Thevenin equivalent circuit then applied KVL from base to ...
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1answer
583 views

Why is Junction Temperature called so?

Why is the silicon die temperature inside a semiconductor device referred to as "Junction" Temperature ? Though this name may make sense for minority carrier devices where there is maximum power ...
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1answer
446 views

Difference between Vth and Vge?

What is the difference between the threshold voltage (Vth) and gate-emitter voltage (Vge) for IGBT devices? How can I calculate Vth of an IGBT chip?
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1answer
33 views

Temperature-Dependent Electrical resistance Si and SiC

In a power electronics device, it seems that silicon carbide (SiC) has a higher variation of electrical on-state resistance with temperature in comparison to silicon (Si). Does anybody know the reason?...
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1answer
140 views

A question about the exact formula for the collector current

Regarding the collector current Ic equation in the below figure: The above figure tells: Ic = Is * (exp(Vbe/Ut)-1) But I thought it should be: Ic = α * Is * (exp(Vbe/Ut)-1) + Icbo 1-) Is α and ...
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1answer
113 views

how does SSD non-volatile storage work

Is it because of the charge present in floating gate that SSDs are able to store information without power? If so, how long would the charge remain in floating gate without electricity?
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7answers
21k views

Why can't I light a LED with a 1.5 V battery?

The LED I am using requires a higher voltage to light than I have supplied, and as a result, it doesn't light at all. I would expect at least a dim light, but light is not generated. Why this ...
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1answer
31 views

Effect of hole conc while doping with donor

Recently i saw a lecture on YouTube there it said that the hole conc is affected by the donor atom and The fermi energy of hole changes due to doping... But since the donor impurity is immobile it ...
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1answer
267 views

Space charge width in a pn junction

There is this formulae we use to determine the space charge width of a pn junction forward biased by Veb and phi-oe represents the built in potential. Now what happens to the space charge width when ...
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2answers
4k views

Does doping always increase the conductivity of a semiconductor?

The conductivity of a semiconductor is given as (if extrinsic): \$\sigma = qnu_e + qpu_h\$ where \$\sigma\$ is the conductivity, \$u_e\$ and \$u_h\$ are the electron and hole mobilities. But does ...
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1answer
529 views

Modelling and simulating multiple-collector/emitter BJTs

I occasionally like to try to understand how well-known integrated circuits work by building them up in a simulator and observing how they respond to changing conditions. However, I keep coming across ...
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1answer
355 views

Solid state circuit breakers

I'm trying to design a Solid state circuit breaker for a 3phase AC system with a rating of 690V, 1000A. As, the stray inductance contributes to the voltage peaks in the system I'm trying to protect ...
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2answers
2k views

MOSFET Depletion Region Widening

I do understand why when drain voltage (\$V_D\$) increases, the channel carriers decrease (the channel narrows), specially near the drain island, eventually reaching pinch-off phase. What I don't get ...
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1answer
453 views

Electron concentration in an intrinsic semiconductor at room temperature

For a Si atom, band gap energy is around 1.1 eV which means that an electron in valence band needs at least this much energy to jump to conduction band. Also, at room temperature, typically energy of ...
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7answers
766 views

Tube and SS amplifier Power

I have heard a lot (!) of misconceptions and anecdotal explanations for why 100w of tube amp is way louder than 100 of solid state (SS) amp. Now, knowing that 100w is always 100w, why is a 100w tube ...
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342 views

Refrigerator relay has a circuit board?

My fridge stopped cooling and kept hearing a click noise every 2-4 minutes. Researching led me to understand the start relay is nothing more than a PTC resistor that cuts the start winding once ...
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1answer
124 views

Component/design recommendations for high power RF switch IC for 1-50 MHz [closed]

In trying to design the circuit, I've been researching the components that are available, and most appear to be focused on the 1-4 GHz range, but some work with lower frequencies. Is there a solid ...
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2answers
9k views

A query regarding Thermal Voltage V = KT

I read thermal voltage = KT ; K in ev/K and T in Kelvin. By substituting we get V = 8.620 * 10^(-5) ev/K * 300K = 0.0259 ev But where ever I read, Thermal Voltage is given as 26 mv but It has to ...
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1answer
70 views

How are few-nanometer multigate MOSFETs fabricated?

Intel and IMEC came up with multigate MOSFET designs with channels as narrow as new nanometers. Which methods/techniques/machines are used to pattern/fabricate such small features? (source) (source)
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1answer
473 views

Silicon controlled rectifier P-type gate connection and layer doping

1). In SCR the gate terminal is connected to the P type semiconductor layer. Can it be connected to N type SC layer? 2). The outer most two layers of the SCR should be highly doped as compared to ...
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1answer
3k views

Why the current across a diode is zero when the forward bias voltage is less than barrier potential?

In the I-V characteristics of diodes under forward bias , I have seen that the current starts increasing from zero only after reaching the barrier potential , say 0.7 for silicon. As far I understand ,...
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2answers
640 views

Do devices on AC currents have flicker on and off?

For current to alternate between positive and negative it must be zero for a split second. Does that mean devices receiving AC current are flickering on and off? This seems like it would have some bad ...
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1answer
52 views

Solar Cell functioning [closed]

I am confused about the operation of solar cell. Maybe its because i still did not quite understand the effect about the voltage drop across a solid state device. We operate in quadrant 4 where ...
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1answer
110 views

How to classify devices into photodiodes, photodetectors and photocells?

Is there a clear differentiation between the three? For example in terms of efficiency (induced current/incident power)?