Summary
- Schottkey barriers are metal-semiconductor
junctions
- Draw band structures -- line up Ef band bend at
semi-conductor edge due to space charge region (depletion)
- Built in voltage as in PN diode -- set by doping
in semiconductor
- Current flow is due to diffusion (emission) over a
barrier
- Which is fixed in one direction and variable in
the other.
- At V=0 currents balance as for PN diode
- Reverse bias lowers semiconductor bands, decreases
the variable current (semi -> metal)
- Forward bias raises semiconductor barriers,
decreases semi/metal barrier, increases current.
- Net result is non-linear exp. I vs V relationship
Questions
- What is a metal/semiconductor barrier called?
- Draw a N-semiconductor/Metal contact band
structure. For
- Equilibrium
- Forward Bias
- Reverse Bias
- What is ther equation for I versus V for a
shottkey diode?
- How do we make ohmic contacts to silicon.