At its most basic form a semiconductor is a material that has electrical conductivity between an insulator and a conductor. Typically silicon is a major component in commercially produced semiconductors; however other materials such as germanium, gallium arsenide, and silicon carbide can be utilized as well. The benefit of a semiconductor is that based on the needs, the value of conductivity can be changed by adding small quantities of other elements known as “dopants”. Semiconductors are the foundation for modern electronics as we know them, seeing as they are found in everything from radios and phones to computers and motors. Semiconductor manufacturing became a viable business in 1960’s and has since become an international market greater than $250 billion US. Semiconductors are a chief technology enabler. Furthermore, they are widely recognized as a core economic driver due to their crucial role in the development of new and more powerful electronic systems, smart phones, computers, automobiles, airplanes, factory equipment and numerous other devices. Semiconductor equipment, the capital equipment used to manufacture semiconductors, is an industry unto itself. The semiconductor equipment companies now serve the solar markets, flat panel television, and other related industries.
There are two basic types of semiconductors; these are N-type and P-type which are determined by the type of doping present in the semiconductor. In N-type doping, phosphorous or arsenic is added to the conductive element, such as silicon, in small quantities. Because of the extra electron freed by adding in phosphorous or arsenic, the electric current flows more easily through the semiconductor. Similarly, with P-type, boron or gallium is used as the dopant, because boron and gallium have fewer electrons than phosphorous and arsenic they create holes in the silicon instead of freeing up electrons and a hole will easily transfer electric current. Both P and N-type semiconductors take a Silicon crystal, which is a fairly good insulator and turn it in a decent conductor, hence the name semiconductor.
What Processes are Semiconductors Involved in? A diode is the simplest device that uses a semiconductor. A diode allows electric current to flow in only one direction, like a turnstile at a stadium. Diodes are used to protect electronic devices if you put the batteries in the wrong way. Until more achievements can be made however, diodes do have a flaw that makes them less than ideal. An ideal diode would completely block current, however a real diode allows about 10 micro amps of current though and if you apply about .7 volts to a silicon diode, the diode will break down and fail completely.
Another common use for a semiconductor is in transistors. A transistor is made up using three semiconductors. Both 2 N-type and 1 P-type or vice versa as opposed to a diode which uses 1 of each. Transistors are devices that control the flow of electrons, and therefore electricity, similar to how a sink faucet controls the flow of water. A transistor will create a sandwich with the similar semiconductors on the outside and the other type in the middle. When a small amount of current is applied to that center layer it acts as a switch that allows much larger current to flow, therefore acting as both a switch and an amplifier. A transistor completely revolutionized electronics design by eliminating the need for vacuum tubes and electromechanical switches. For example, the first computer, known as ENIAC, which used over 17,000 vacuum tubes and weighed nearly 30 tons, is a far cry from the phones and computers of today.
What are the Advances with Semiconductors in the Near Future?
Advances in semiconductor chemistry in the past several decades have vastly transformed electronics as we know them. Engineers have started working with other doping materials such as zinc selenide and gallium nitride which will function better in electronics that produce more heat and operate at higher temperatures (such as sensors in car engines). It is very difficult experimenting with new elements however because it is not known how many will react once meshed with the silicon and a high failure rate is becoming a common theme. The most recent accomplishment showed the scientific community a lot about what is still possible. When a 45 mm microprocessor recently produced using a hafnium based semiconductor, many realize that scaling will eventually not be enough to sustain the ever-increasing demand.