I believe if technology was gained from a crashed UFO in 1947 it was more about understanding that circuits could be miniaturized and interconnected; Not that we learned about how to make a semiconductor transistor. It's all about planting a seed of thought and going "I wonder if we could interconnect circuits in a similar fashion". Some say that fiber optics may have come from the UFO. Again, maybe it just planted the seed that maybe we could transmit data more quickly though a "transparent wire" and we mimicked it by using glass and eventually plastics. More of "that an interesting idea/concept....let's try to use that idea and see what we can come up with".
The first integrated circuits were separately developed and announced by Bob Noyce at Fairchild Semiconductors and Jack Kilby at Texas Instruments in 1959. Kilby did it in germanium, and Noyce in silicon (using a more practical planar manufacturing process), but the concept went all the way back to the 1920's when engineers miniaturized and combined multiple vacuum tubes inside a single package. Once the invention of the transistor was announced, engineers immediately began to consider how multiple transistors could be combined in the same package.
In a more practical sense, miniaturization and integration of components went all the way back to 1510 with the invention of the first pocket watch. Engineers were applying it to mechanical systems long before the invention of vacuum tubes in the early 20th century. The advantages of such systems were obvious to everyone; it was only a matter of figuring out the manufacturing processes to make them practical and economical.
Anyone who learns about microelectronics or fiber optics will find that the original principles date back to the 19th century. Those who claim that they came from UFOs fall into the logical fallacy of "a lot of new inventions appeared after this particular date, so there must be something special about that date". One could just as easily claim that every significant technical advancement after 1947 came from a UFO crash. What was really happening was exponential technological development as a consequence of the industrial age and the scientific method, dating back to the 1700's.
You can arbitrary pick any random date in the 20th century and show that technology advanced exponentially after that date. For example, one could argue that modern smartphones were invented because alien communicators were found in the Roswell crash, while ignoring the history of portable communications devices going back to the 1920's.
As I said, the development of every major technological advance is meticulously documented in the technical literature. Engineers and scientists are every bit as imaginative and clever as any theoretical alien. One thing that I've learned in my career is that there are people you will meet who aren't just smart; they are absolutely brilliant in a way that even your typical "smart" person can't grasp. They come up with new ideas that literally seem to drop from the heavens, but they didn't learn them from space aliens. They were just very smart and creative.
