所屬科目:中山◆電機◆半導體概論
1. What range of impurity gradient should be considered if we want to obtain the breakdown voltage = 250 to 750 V in a linearly graded Si p-n junction? Assume the breakdown maximum electric field =2.5 x 105 V/cm, = 11.9.
2. Copper is deposited on an n-type Si substrate to form an ideal Schottky diode. = 4.65 eV, the electron affinity is 4.01 eV, cm3. Calculate the barrier height, the built-in potential, the depletion-layer width, and the maximum field at zero bias. T = 300K. Effective density of states in conduction band is 2.86 X .
3. Derive the depletion layer width of a p-n junction. Doping concentrations are . Dielectric constant is and the built-in potential is .
4. Calculate the emitter injection efficiency. Assume the following transistor parameters:Doping concentrations in base and emitter are and . Widths of neutral base and enitter are = 0.8 um and = 0.5 pm.Minority carrier diffusion coefficients in base and emitter are = 20 cm2/s and = 10 cm2/s.
5. Calculate the threshold voltage shift due to short-channel effect. Consider an n-channel MOSFET with , channel length L = 1 um, diffused junction depth = 0.3 μm, oxide thickness , and dielectric constant of oxide is 3.9.