All Questions
Tagged with semiconductors physics
42
questions
1
vote
1
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67
views
Limit of applicability of "quasistatic"/capacitive picture of devices
When analyzing the transitories associated with switching in semiconductor devices, in textbook treatments one often sees the time dependence considered by including (potentially nonlinear) capacitors ...
- 1,161
1
vote
1
answer
97
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Confusion about why pn junction discussion insensitive to doping variations faster than Debye length
Sze (Physics of Semiconductor Devices, 3e) gives the following discussion which relates to how equilibrium electric fields/equilibrium potential build-up at thermal equilibrium are related to doping ...
- 1,161
1
vote
3
answers
70
views
Seebeck Voltage [closed]
I understand that the voltage of two metal elements is V=(Sb-Sa)(T2-T1) regarding a thermocouple. But, what if mass was introduced to find the voltage? Can mass also be used to find voltage with ...
- 11
1
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1
answer
552
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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)$...
- 121
3
votes
1
answer
269
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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?
- 47
2
votes
0
answers
190
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MOSFET gate substrate voltage
In a MOSFET the channel is formed between gate and the body it would sense to use gate body voltage to form the channel. Why is gate source voltage used to form the channel?
5
votes
1
answer
634
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What is the correct carrier concentration equation to use?
In this book I am reading, it gives the intrinsic carrier concentration as:
\$ n_i = \sqrt{N_c\cdot N_v} \cdot e^{({\frac{-E_g}{2*K*T}})} \$
While another book says the carrier concentration is:
\$ \...
- 341
2
votes
2
answers
1k
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Why does the majority carrier concentration near the junction not decrease under forward bias? (PN junction)
We see that the current due to the majority carrier decreases near the junction as shown above, which means the majority carrier concentration should also decrease since the diffusion current is given ...
- 437
0
votes
1
answer
797
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Given a energy band diagram, can you always calculate potential, electric field, and charge distribution?
Given a band diagram, where do you start to get the electric field and charge distribution?
- 437
0
votes
4
answers
1k
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BJT Early effect and the small signal model
As the collector-emitter voltage changes, collector current changes due to the Early effect so the base current must also change.
In the small signal model, we only account for the change of collector ...
1
vote
1
answer
334
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Physics of BJT and charge profiles
Why does a linear charge profile in the base imply no recombination of charges at the base, but in case exponential decay it implies recombination at the base?
Why does charge density at the base ...
4
votes
4
answers
867
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GaN Vs SiC physic properties
Here is a table which shows the différence between GaN and SiC:
I have no knowledge about physics of components. I have just some bases. In the above table I do not see real difference between SiC ...
- 2,434
0
votes
1
answer
179
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In semiconductor physics, how can we know which units to use for Boltzmann's constant?
I'm working through Example 3.9 from Sima Dimitrijev's Principles of Semiconductor Devices textbook, and I'm not sure how to know which units to use for k in solving for \$v_{th}\$ in part a. The ...
- 87
6
votes
2
answers
3k
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Depletion Region Capacitance in MOSFET
Hi, I would like to ask about the behavior of a MOSFET as a capacitor, particularly at the onset of inversion/weak inversion - see Fig 2.6(c)
At this stage in Fig 2.6(c), there is positive charge at ...
- 3,125
1
vote
1
answer
279
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Semiconductor diffusion current over time
Suppose you have an injection of holes into a semiconductor such that at some time you have this linear hole profile:
Because the diffusion current at any point is proportional to the slope of P at ...
- 677