Silicon at T-300K is uniformly doped with Boron atoms to a concentration of 5x10 cm and...

 

Transcribed Image Text:

Silicon at T-300K is uniformly doped with Boron atoms to a concentration of 5x10 cm and with Arsenic atoms to a concentration of 2x10 cm. a) Is the semiconductor a type or p type? Calculate the thermal equilibrium concentrations of majority and minority carriers, position of the Fermi level and the conductivity of the semiconductor. b) Additional impurity atoms are added such that the Fermi level is 0.26eV below the conduction band edge E. What type and concentration of the impurity atoms must be added? Calculate the new concentrations of the majority and minority carriers and the conductivity of the semiconductor. Q2. (30 points) 100 The Hall effect device has the dimensions = 8cm, w=1.5cm, d=2cm and electrical parameters /=24, V=251. B=50kGauss - STesla. The Hall Electric field is measured between the front and rear plates and Gas +4- M cm a) Determine the type of the semiconductor, b) Calculate the majority carrier concentration, c) Calculate the majority carrier mobility. Q3. (40 points) Consider a uniformly doped GaAs pn junction at T-300K. At zero bias, 40 percent of the total space charge region is in the p region (x,-0.4xW, ). The built in potential barrier is V = 1.2V and the relative dielectric coefficient of GaAs is given as c=13.1. The pn junction has the following parameters: 1), -90 D, 5.72 t=0.02μs. t=0.05μs and A=6x10 cm. a) Calculate N, No. XX . Assuming a forward bias of V=0.9x V is applied to the pn junction, calculate: b) Hole concentration at x = x,, c) Hole diffusion current density at x = x,, d) Electron concentration at x=-x,. e) Electron diffusion current density at x = -x,₁ f) Total current of the pn junction. Silicon at T-300K is uniformly doped with Boron atoms to a concentration of 5x10 cm and with Arsenic atoms to a concentration of 2x10 cm. a) Is the semiconductor a type or p type? Calculate the thermal equilibrium concentrations of majority and minority carriers, position of the Fermi level and the conductivity of the semiconductor. b) Additional impurity atoms are added such that the Fermi level is 0.26eV below the conduction band edge E. What type and concentration of the impurity atoms must be added? Calculate the new concentrations of the majority and minority carriers and the conductivity of the semiconductor. Q2. (30 points) 100 The Hall effect device has the dimensions = 8cm, w=1.5cm, d=2cm and electrical parameters /=24, V=251. B=50kGauss - STesla. The Hall Electric field is measured between the front and rear plates and Gas +4- M cm a) Determine the type of the semiconductor, b) Calculate the majority carrier concentration, c) Calculate the majority carrier mobility. Q3. (40 points) Consider a uniformly doped GaAs pn junction at T-300K. At zero bias, 40 percent of the total space charge region is in the p region (x,-0.4xW, ). The built in potential barrier is V = 1.2V and the relative dielectric coefficient of GaAs is given as c=13.1. The pn junction has the following parameters: 1), -90 D, 5.72 t=0.02μs. t=0.05μs and A=6x10 cm. a) Calculate N, No. XX . Assuming a forward bias of V=0.9x V is applied to the pn junction, calculate: b) Hole concentration at x = x,, c) Hole diffusion current density at x = x,, d) Electron concentration at x=-x,. e) Electron diffusion current density at x = -x,₁ f) Total current of the pn junction.