Lab ID: SOG and Metallization

Your goals this week are to learn how to deposit aluminum and to dope silicon using spin-on glass. 

I. Load sample for metallization.

  1. Follow the metallization procedure and go through phase I: loading the sample and start pumping it down.  The sample will simply be a glass slide. It will take > 30 minute sto reach a sufficient base pressure so go on to part II at this stage. 

II.  Apply Spin -on Glass

  1. Obtain 2 "quarters" of an n-type wafer and 2 "quarters" of a p-type wafer.
  2. Apply boron-doped SOG to the n-type and phosphorous-doped SOG to the p-type pieces. Follow the guidelines in the SOG procedure.
  3. Place wafers in the diffusion oven. different groups will look at different temperature:

    Group A:  950 ºC

    Group B:  1000 ºC

    Group C:  1050 ºC

    Group D:  1100 ºC

    Program the oven for a 45 minute ramp and a 30 minutes dwell. N2 should be flowing at full scale throught the oven.  Programming the diffusion oven is identical to what is described on the dry oxide and wet oxide webpages.

  4. At a subsequent lab we will remove the wafers, strip the SOG using  the BOE solution, and measure sheet resisitivity.

 

III. Evaporate Aluminum

  1. After starting the SOG furnaces return to the evaporator and finish aluminum deposition.
    2.
  2. Remove the glass slide and  and characterize the aluminum thickness with thte profilometer.
  3. Measure the sheet resistance of the aluminum.
  4. At a subsequent lab we will anneal the glass slides and  repeat measurements of thicknesss and sheet resisitivity.