Week 4: Eliminate analysis question on polysilicon deposition rate. (It was about 0.5 microns in 50 minutes.)

Week 5: You were not asked to record the color of the monitor (although it is generally a good idea when measuring oxide thickenss), so just state this in question 4 if you don't have the information.

Note that the web site has the implant information.

For questions 5 and 6, you may make the simplifying assumption to ignore the effects of the initial phosphorus implant. This will make computing the junction depth and sheet resistance easier. If you do want to include the phosphorus diffusion, D=3.9 exp (-3.66/kT) at low concentrations.

The sheet resistance computation is covered in the example posted on the web site. To do the integral, just break the diffusion up into about 10 layers conducting in parallel and add up the conductivities like conductors in parallel. This is the easiest way of doing the numerical integration. Note that each layer will have a doping (from your concentration calculation) and that this doping will correspond to a resistivity (and therefore a conductivity) from the chart from Sze on the web site.

We haven't covered the material for question 7, so this can be skipped.

Weeks 7 and 8:

Question 2: The resistivity of thin-film aluminum is lower than that of bulk aluminum because electrons experience more scattering in thin films than in the bulk. Reasons include scattering off the top and bottom of the film, grain boundary scattering from smaller crystals, and scattering from impurities, particularly oxygen in sputtered films. It is not unusual to have the measured resistivity be 2 or even more than 2 times the bulk resistivity.

Question 4: Do not compute the doping concentration.

Question 5: We have been having some problems with the C-V measurements. As a consequence, the capacitance may have a zero offset, and even if this is corrected may not be the right value. The shape should be qualitatively correct, and should correlate well with the threshold voltage, but oxide thickness calculations are likely to be misleading.

Approximately what is the threshold voltage, just looking at the curve (no calculation)? Don't worry about the flatband voltage.

Question 9: Change to - Plot the forward and reverse diode characteristics on a linear scale. Do they look qualitatively as expected?

Quesion 10: Just report the reverse breakdown voltage.

Question 11: We will not be calculating the theoretical value of the threshold voltage, but you can (if you have the C-V measurements) qualitatively compare the threshold voltage from the VDS=0.1V measurements with the C-V curve. You will not be able to compute the oxide charge.

Question 12: The bulk value of hole mobility is roughly 400 cm2/V-s. This value decreases due to scattering at the Si-SiO2 interface.