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Microfabrication extra exercises 2013 . Questions 1-6 each 1 point, Question 7, 2 points. Return to Moodle by January 11 th , 2014. Plot growth rate as a function of inverse temperature for SiH 4 epitaxy and explain the shape of the curve ! 700 750 800 850 900 950 1000 1050 1100
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Microfabrication extra exercises 2013 Questions 1-6 each 1 point, Question 7, 2 points. Return to Moodle by January 11th, 2014
Plot growth rate as a function of inverse temperature for SiH4epitaxy and explain the shape of the curve ! 700 750 800 850 900 950 1000 1050 1100 0.04 0.09 0.2 0.4 0.5 0.6 0.7 0.75 0.8µm/min 2. If silane (SiH4) flow in a single wafer (150 mm) PECVD reactor is 5 sccm (cm3/min), what is the theoretical maximum deposition rate of amorphous silicon ? 3. Consider professor’s Mazda 6 filled with golf balls and one squash ball (passanger compartment and trunk) . If golf balls represent silicon atoms, and the squash ball represents a phosphorous atom, what would be the resistivity of a silicon piece with similar doping level? 4. What changes if boron implantation is replaced by BF2+ implantation ? 5. How many LPCVD tubes are needed in a 30 000 WPM fab if the process has five polysilicon layers ? 6. What etch selectivity is needed to release 1 µm thick silicon nitride plate of 50 µm width by sacrificial oxide etching (49% HF, rate 2 µm/min), if plate thickness variation due to etching has to be smaller than nitride deposition non-uniformity of 3% ? 7. Explain step-by-step the fabrication of the tuneble capacitor shown below. Estimate dimensions etc.