What is the resistivity of intrinsic silicon

To from the carrier density n to Conductivity = q · n · Μ to come, we still need them µ the load carrier.The mobility µ has already been mentioned several times; we had:
  1. The definition of µ.
  2. The relationship between µ and fundamental variables such as drift speed, mean free path or time between two collisions.
  3. The calculation of µ for several simultaneous collision processes.
  4. The experimental determination of µ with the help of the Hall effect.
  5. The relationship between the maximum frequency of a component and µ.
It was also mentioned that mobility is a fundamental material parameter and does not only appear in formulas for conductivity.In addition, we have already regretted that we are unable to find formulas for mobility here.All of this, plus some further considerations, are summarized in a separate module. Anyway, here we just need to look at two things:
  1. The mobility increases with increasing temperature. We have already considered this for the intrinsic case, and there is little that will be able to change that in the case of doped semiconductors.
  2. The mobility is reduced by collisions with foreign atoms. Doping atoms are foreign atoms, so we have to ask ourselves whether doping affects mobility.
The answer to the question in point 2 is:. The mobility is reduced by doping (this is bad because we obviously also reduce the cutoff frequency of a component). But at the same time the temperature dependence of the mobility is reduced, since collisions with phonons play an increasingly smaller role with increasing doping concentration.What we get in total typically looks like this:
In extreme cases, the mobility is reduced by about an order of magnitude by doping at room temperature; there is the decrease of µ only really noticeable at higher dopant concentrations.The curves for electrons are similar, but there can be a factor in the absolute value 10 appear - depending on the semiconductor and the detailed band structure. For example, the mobility of electrons in silicon is roughly one factor 3 larger than that of the holes. 
   If we take the approximately linear dependence of the charge carrier density and the comparatively small but non-linear dependence of the mobility on the and multiply both together, we get the specific conductivity or the specific resistance = 1/ as a function of the dopant concentration.For silicon it looks like this:
These are some of the most important curves of modern mankind. The is based on them.Any product manufacture in the Si Technology begins with careful consideration of which doping type and which basic doping you start with (usually in the area (10-0.5) cm)When making a crisps, so one integrated circuit, then locally up to 10 differently endowed - that's what the. That, just to differentiate between them, is based on how you connect the components to each other. That is essentially no longer the case Si instead, but that Si.

© H. Föll (MaWi 2 script)