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Laboratory: A Typical Wet Etching Process. - Prepare chemicals. - Mix chemicals in the proper ratios. - Heat chemical mixture. - Etch wafer. - Remove wafer from the chemical etch solution. - Rinse wafer. A Typical Dry Etching Process. - Prepare chamber. - Load wafers. -Plasma etch.
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A Typical Dry Etching Process
- Prepare the source wafers (e.g., ceramic wafers of LnP5O14 , which is a mixture of Ln2O3 and P2O5, as a source of P2O5 for P-doping).
- Verify that the diffusion furnace temperature is set (~ 850 °C for P ).
- Using teflon or teflon-tipped tweezers, carefully load the wafers into the quartz boat.
- The wafers should be inserted such that the device side of each is facing an P2O5 source wafer. There are two wafer slots between sources, allowing for a device wafer facing both sides.
- Return quartz boat, which now contains the wafers and sources, to the phosphorus furnace using the quartz boat loader.
- The phosphorus furnace needs to be heated to the temperature (~850 °C for P-doping) at which the diffusion will be performed.
- Begin nitrogen flow through the tube by setting the gas flow rate to a reasonable value (~3000 sccm).
- At the end of the process remove the boat from the furnace and allow the wafers to continue to cool before removing them from the wafer carrier.