Making Homemade Transistors
After 20 years, Where I am in the race of "Do it yourself transistors"? (9/24/2009)
On 1987, I learned about how computer and digital gates works. On 1988 I made a full schematic of a calculator with transistors. On 1989 I decided to make a transistor.
Today, 20 years later, where I am?
Unfortunately, I am too far away from the finish line. I am writing this because I finally gave up. I am out of the race.
Back in 1991, I was "close" to make a transistor. Experimenting with some metals, I found that the oxide of copper have some interesting features and a transistor can be made of it, but the results were different. It was kinda random so I did not consider it an achievement.
On 1998 I did learn how the first transistor was "invented"1. A simple contact-point transistor was not easy because the results are random and not efficient.
On 2007 I started to retake the idea. I got some information from DrDR saying: "I am a little surprised that it would be considered 'difficult' to make a transistor. I used to make them for a living, and design the manufacturing process for the specific characteristics desired. A bipolar transistor is a device made up of material with three densities of doping of the semiconductor material. From a production point of view, doping in exact amounts are important to determine the exact voltage the transistor turns on or off. A crude transistor can be made by dipping a flat crystal into liquid doped semiconductor so that a thin film hardens which matches the underlying crystal, then changing the dope concentration before the next dip. This process is called "liquid phase epitaxy", and is used to make transistors, diodes, LEDs, semiconductor lasers, and resistors using semiconducting materials made from two or three elements, such as Gallium Arsenide(GaAs), or Gallium-Aluminum-Arsenide(GaAlAs)."
Sounds like a great idea but there was not details, so I was not able to reproduce this process.
Oh, by the way, if you think that you can connect two diodes to make a transistor, don't waste your time. You need to learn how do transistors really work.
Nyler Steiner was able to make a homemade FET Transistor with a CDS Photocell but still not a truly "homemade" or "diy" as the process of creating semiconductors are not done. But still interesting anyway. Mr. Steiner indicates he got the idea after reading Roger Bake notes about a DIY FET/home-made transistor.
Finally, I have learned how to make homemade semiconductors thanks to Jeri Ellsworth. I found that I'm not able to make one because economic reasons. The equipment needed is quite expensive. The process is not complex but it needs to be done with trials and errors. Baby steps are the key to reach the goal.
In case you are interested about how to make homemade semiconductors, including solar cells, diodes, transistors or even a homemade Integrated Circuit, Here is a 40 minutes video explaining the manufacture process:
Sorry Snoopy, you are not my hero anymore. From now, Jeri Ellsworth is my hero.
To learn more:
Julius Edgar Lilienfeld proposed the basic principle behind the MOS field-effect transistor in 1925.
Jeri Ellsworth's setup to build simple transistors and IC's at your home. Also, A homemade IC made by Jeri.
1 Some people believe the transistor was invented by Julius Edgar Lilienfeld in 1925, long before it was "invented" in 1947 by three American physicists at the Bell Telephone Laboratories. Others claims the contact-point transistor was know long before the geniuses at Bell laboratories invented it.
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