Question

1. Compute the resistivity of an intrinsic semiconductor at 300 K, in units of Ω-m, given that it has an intrinsic carrier concentration of 4.9 x1022m-3 and electron and hole mobilities of 0.53 and 0.09 m2/V-s, respectively.

2.

The intrinsic concentration of electrons and holes (i.e. concentration of e-h pairs) in Si at room temperature is approximately 1x1010 cm-3.

Given the density and atomic mass of Si to be 2.33 g/cm3 and 28.06 g/mol, determine the ratio of ionized to unionized Si atoms in the lattice.

Note:In this question you are essentially trying to figure out the concentration of broken bonds in Si at room temperature as each broken bond leads directly to one free electron-hole pair.

Assume that each Si atom can be ionized only once (only one of its 4 covalent bonds can be broken).

3. Calculate the resistivity of Si doped to a concentration of 2x1018 m-3 boron (B) atoms, given that the mobilities for electrons and holes in silicon are 0.14 and 0.05 m2/V-s, respectively.

Answer 1

1)

2)