The p-type region of a silicon p-n junction is doped with 1016 boron atoms per cubic centimeter, and the n-type region is doped with 1018 phosphorus atoms per cubic centimeter. Assume a step p-n junction and that all doping atoms are ionized. The intrinsic carrier concentration in silicon at 300K is 1.5∗1010cm−3.
What are the electron and hole concentrations (in cm−3) in the p-type and n-type regions at thermal equilibrium?
Hole concentration in p-type region (in 1016cm−3) :
1
2.25
1
225
0.8
0.325
To determine the hole concentration in the p-type region at thermal equilibrium, we need to consider the doping concentration and the intrinsic carrier concentration.
In the p-type region, the doping concentration is given as 1016 boron atoms per cubic centimeter, which translates to 1016 cm-3.
At thermal equilibrium, the hole concentration (p) in the p-type region can be calculated using the equation:
p = (ni^2) / Nd
Where:
- p is the hole concentration in the p-type region
- ni is the intrinsic carrier concentration (given as 1.5*10^10 cm-3)
- Nd is the doping concentration in the p-type region
Plugging in the values, we have:
p = (1.5*10^10)^2 / 10^16
Simplifying the equation, we get:
p = 2.25 * 10^10 / 10^16
p = 2.25 * 10^-6 cm^-3
Therefore, the hole concentration in the p-type region is 2.25 * 10^-6 cm^-3, which is equivalent to 2.25 * 10^10 per cubic centimeter (in 10^16 cm^-3).