Physics of Semiconductor Devices

Return to
problem list

      

Diffusion current

The phosphorous concentration in a region of a silicon crystal varies linearly from a concentration of 800000000000000000 cm-3 at x = 0 to a concentration of 7000000000000000 cm-3 at x = 1 mm. The diffusion constant for electrons is 22.5 cm²/s, the diffusion constant for holes is 5.2 cm²/s, and the temperature is 300 K. What is the diffusion current density in the positive x-direction?

J = A/cm²