3. Unipolar Devices 3.1 The Metal-Semiconductor (m-S) Junction

3. unipolar devices 3.1 the metal-semiconductor (m-s) junction

The traditional derivation of the M-S junction electrostatics is based on the full depletion approximation which assumes that the semiconductor is depleted over a distance xd, called the depletion region. A comparison of the correct solution and the solution obtained when using the full depletion approximation can be found in figures 3.3 through 3.6. Having the semiconductor depleted of free carrier over a distance xd implies the following charge density for n-type material : ρ = q Nd ρ=0 0 < x < xd xd < x [3.