# Charge carrier screening in semiconductor

Dear physics forums users,
I'm reading a paper saying "For hole density $p\sim 10^{17} - 10^{18}/cm^3$, the screening length in silicon, $\lambda_{Si}$, is ~1-2nm."
For this, the paper references Sze's, Physics of Semiconductor Devices.
I'm unable to find the formula by which the authors seem to be calculating this screening length in the book. Can somebody point me out on where to find it?

Thanks for hints.