Unformatted text preview: b. Compute the thickness of each of the three layers. Sketch and label the layers. c. Discuss how much longer the dry/wet/dry process takes compared to a pure wet oxidation, but how much time is saved compared to a pure dry oxidation. 3. Explain why some silicon is consumed during thermal oxidation, and derive the equation x Si consumed = 0.46 x ox . 4. Explain whether the residual stress in thermally grown oxide is compressive or tensile and give reasons why. Research typical stresses in thermally grown oxide and give references. 5. A device fabrication involves depositions of Al, Cr, Si 3 N 4 , and SiO 2 . For each material, choose a deposition process (PVD or CVD). For PVD, specify Evaporation or Sputtering; for CVD, specify LPCVD or PECVD. Explain each of your choices. Hint: Temperature and quality....
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- Fall '08
- Chemical vapor deposition, Thermal oxidation, MEMS Transducers, thermally grown oxide