Start of the third week

I spent most of Monday in the clean room.  In the morning I was part of the group being shown how to do an evaporation onto the wafers we made last week.  During the evaporation process, a very thin layer (about 10 nanometers) of chromium was deposited onto the surface of my wafer.  The machine that performs the evaporation procedure first creates a very low pressure (3 x 10-6 Torrs) in the container where the wafers are stored.  Once the proper pressure is obtained, then an electrode heats up the metal until it vaporizes.  The vapors are then allowed to deposit onto the surface of the wafer at a controlled rate.

Once the deposition of the metal was completed, we completed the lift off procedures by first placing the wafer in a bath of acetone.  The acetone removed all the chrome that was not in the area of the photoresist.  The wafer is then rinsed in methanol and finally cleaned with DI water and dried with nitrogen.  We will continue to work with our wafers next week.

During the afternoon Marvin and I worked with Yan to make the second and final evaporation of gold onto our sensor chips.  The difference for this procedure was that the chips were mounted into the evaporator at an angle so that gold nanorods would be created.  We applied approximately 500 nm of gold on the surface of our chips.  Tomorrow we are scheduled to inspect the chips using a scanning electron microscope.

During lunch we had Dr. Bifano speak to us about adaptive optics and his experience with start-up businesses.  He was a great speaker and provided good graphics to explain the complicated concepts he discussed.  Since starting the RET I have notice how important the concept of entrepreneurship is stressed to the students at BU.  The goal is to take what it developed in the labs and bring it to industry.