Semiconductors: The Silicon Chip
Silicon is the raw material most often used in integrated circuit (IC) fabrication. It is the second most abundant substance on the earth. It is extracted from rocks and common beach sand and put through an exhaustive purification process. In this form, silicon is the purist industrial substance that man produces, with impurities comprising less than one part in a billion. That is the equivalent of one tennis ball in a string of golf balls stretching from the earth to the moon.
Semiconductors are usually materials which have energy-band gaps smaller than 2eV. An important property of semiconductors is the ability to change their resistivity over several orders of magnitude by doping. Semiconductors have electrical resistivities between 10-5 and 107 ohms. Semiconductors can be crystalline or amorphous. Elemental semiconductors are simple-element semiconductor materials such as silicon or germanium.
Silicon is the most common semiconductor material used today. It is used for diodes, transistors, integrated circuits, memories, infrared detection and lenses, light-emitting diodes (LED), photosensors, strain gages, solar cells, charge transfer devices, radiation detectors and a variety of other devices. Silicon belongs to the group IV in the periodic table. It is a grey brittle material with a diamond cubic structure.
Silicon is conventionally doped with Phosphorus, Arsenic and Antimony and Boron, Aluminum, and Gallium acceptors. The energy gap of silicon is 1.1 eV. This value permits the operation of silicon semiconductors devices at higher temperatures than germanium.
Now I will give you some brief history of the evolution of electronics which will help you understand more about semiconductors and the silicon chip. In the early 1900’s before integrated circuits and silicon chips were invented, computers and radios were made with vacuum tubes. The vacuum tube was invented in 1906 by Dr.Lee DeForest.
Throughout the first half of the 20th century, vacuum tubes were used to conduct, modulate and amplify electrical signals. They made possible a variety of new products including the radio and the computer. However vacuum tubes had some inherent problems. They were bulky, delicate and expensive, consumed a great deal of power, took time to warm up, got very hot, and eventually burned out. The first digital computer c...
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..., the second mask pattern is exposed to the wafer, and the oxide is etched away to reveal new diffusion areas. The process is repeated for every mask - as many as 18 - needed to create a particular IC. Of critical importance here is the precise alignment of each mask over the wafer surface. It is out of alignment more than a fraction of a micrometer (one-millionth of a meter), the entire wafer is useless. During the last diffusion a layer of oxide is again grown over the water. Most of this oxide layer is left on the wafer to serve as an electrical insulator, and only small openings are etched through the oxide to expose circuit contact areas. To interconnect these areas, a thin layer of metal (usually aluminum) is deposited over the entire surface. The metal dips down into the circuit contact areas, touching the silicon. Most of the surface metal is then etched away, leaving an interconnection pattern between the circuit elements. The final layer is "vapox", or vapour-deposited-oxide, a glass-like material that protects the IC from contamination and damage. It, too, is etched away, but only above the "bonding pads", the square aluminum areas to which wires will later be attached.
Microelectromechanical Systems (MEMS) are systems that are designed on a micro metre scale and have become more popular as the demand for devices to get smaller has increased. The main uses of these systems are for sensors, such as accelerometers and gyroscopes and other such devices like microscopy and inkjet nozzles for example. There are many materials that can be used for MEMS as the cost of the material is almost eradicated due to the micro size of the systems being produced. This brings materials such as gold, platinum and diamond can be used, as these materials have some properties which are very desirable for a MEM systems. The most common material that is currently used in MEMS is silicon and silicon based compounds as they possess many good properties for MEMS production. Most of the materials chosen for MEMS are semiconductor materials Figure 1 shows the properties of commonly used materials.
...wouldn't it?’"(Lee 276). She understands that like a mockingbird, Boo Radley had done harm to no one and didn't deserve the unfair attention of the town about his sanity. The other very important lesson Atticus teaches Scout is empathy. After Scout gets into trouble for making fun of Walter Cunningham for pouring syrup on his food, Atticus tells her she will get along a lot better in life if she learns to walk around in other people's shoes. This is a lesson that takes Scout some time to learn, but by the end of the novel it is clear that Scout learns empathy.
Herman Hollerith (1860 - 1929) founded IBM ( as the Tabulating Machine Company ) in 1896. The company renames known as IBM in 1924. In 1906 Lee D. Forest in America developed the electronic tube (an electronic value). Before this it would have been impossible to make digital electronic computers. In 1919 W. H. Eccles and F. W. Jordan published the first flip-flop circuit design.
One of HP's innovative efforts include innovations in their use of resources. One of these innovations is the development of the transparent transistor technology which utilizes low-cost and high-efficiency materials such as tin and zinc. With minimal environmental impact, these materials also allow HP for faster mobility of resources world-wide,...
Leonardo da Vinci was born in 1452 in Anchiano, Tuscany. He was born out of wedlock to a poor woman named Caterina. Caterina married a notary, Ser Perio, around the time he was five. His father taught him basic reading, writing, and math. He also helped to develop his talent in art. Around the time da Vinci was fifteen he became apprenticed to the artist Andrea del Verrocchio. He also painted an angel in Verrocchio’s painting “The Baptism of Christ.” When he was twenty-six he became an independent master of art. A few years later, he started doing his first commissioned works.
Many people know Leonardo da Vinci as only an artist, but he was so much more than that. Not only did Leonardo paint and draw, he also invented and learned new things about science in his everyday life. Leonardo was born on April 15, 1452 (Ryan and Daigle). His home village was Vinci near Florence, Italy (Goodenough 38). Leonardo’s death occurred in court of King Francis I on May 2nd, 1519 (Goodenough 11). He was very gifted and talented. Painting was not all that he did. Leonardo was also an architect, engineer, sculptor, and a musician. He would make outfits for pageants and prepare text and illustrations for books. He even wrote the book “Treatise on painting”, worked as a military engineer, and made diagrams for important books in mathematics (Chase 68). Leonardo
Leonardo da Vinci was born on April 15,1452 and died May 2, 1519 at the age of 67. His parents were Piero da Vinci and Caterina that lived in Florence. He was an Italian man with lots of interests including inventing inventions, painting, sculpting, science, music, engineering, mathematics, literature, geology, botany, architecture, history, writing, and many other areas. He is most known as an artist in history. He is considered one of the greatest painters of all time. Lots of the historians call him the “Renaissance Man” because he was such a curious man with an outstanding imagination. He created many paintings and drawings that made an impact in history in several ways.
Leonardo da Vinci was born on April 15, 1452 in a small Tuscan town called Vinci that was near Florence. Most people know him for his skills as an artist and his many famous paintings. These paintings included the Mona Lisa, The Last Supper, and Virgin of the Rocks. An artist was only one of the activities that da Vinci was good at. He was known as the quintessential Renaissance man. Da Vinci was also a mathematician, inventor, sculptor, musician, and writer. Leonardo is stated to be one of the most diversely talented men maybe ever to be alive. He studied at the studio of Verrocchio in Florence in his younger years. Studying with Verrocchio he was introduced to many different challenges to paint and that ended up diversifying his styles and abilities.
...eas of high knowledge and if he had published his ideas to the public, the course of history would’ve been very different. After completing all his work, Da Vinci was asked to travel to Rome in 1513 by Pope Leo X. There he was given a studio in the Vatican and planned to stay there for four years. In 1517, Da Vinci was invited by King Francis I to stay in an apartment in the palace at Cloux. There he would train many young students since he had developed paralysis in his right hand and couldn’t complete new work. Leonardo then died in Cloux on May 2nd, 1519. “What most impresses people today is the wide range of Leonardo's talent and achievements. He turned his attention to many subjects and mastered nearly all. His inventiveness, versatility, and wide-ranging intellectual curiosity have made Leonardo a symbol of the Renaissance spirit” (“Leonardo Da Vinci”, David).
Silicon surface micromachining uses the same equipment and processes as the electronics semiconductor industry. There are three basic building blocks in this technology, which are the ability to deposit thin films of material on a substrate, to apply a patterned mask on top of the films by photolithographic imaging, and to etch the films selectively to the mask. A MEMS process is usually a structured sequence of these operations to form actual devices.
Computer engineering started about 5,000 years ago in China when they invented the abacus. The abacus is a manual calculator in which you move beads back and forth on rods to add or subtract. Other inventors of simple computers include Blaise Pascal who came up with the arithmetic machine for his father’s work. Also Charles Babbage produced the Analytical Engine, which combined math calculations from one problem and applied it to solve other complex problems. The Analytical Engine is similar to today’s computers.
Grundmann, Marius. Physics of Semiconductors: An Introduction Including Devices and Nanophysics. New York: Springer, 2006. Print.
Silicon (Si) is the best-known semiconductor. Boron, germanium zinc sulfide, Mercury selenide are some the few of hundreds of semiconductors. Semiconductors also could be found in nature like zinc selenide (ZnS), cuprite (CU2O) and galend (PbS). Semiconductors are classified in numerous ways. They exist as pure elements such as Si, B and compounds such as gallium arsenide. Semiconductors could also be categorized as Elemental, Binary and Ternary.
By the time the 20th century arrived, vacuum tubes were invented that could transmit weak electrical signals which led to the formation of electromagnetic waves that led to the invention of the radio broadcast system (750). These vacuum tubes were discovered to be able to transmit currents through solid material, which led to the creation of transistors in the 1960’s (750).
Silicon is a metalloid and has the atomic number of 14 on the periodic table of elements. It is one of the most abundant elements in the universe, and usually is contained in dirt, soil, sand, and it makes up of about 27.7% of the Earth’s mass (Abundances of the Elements in the Earth's Crust, , Hyperphysics, Georgia State Univ.). One of the special features of silicon is that it is a semiconductor. This means that under certain circumstances, silicon will conduct electricity. Scientists have harnessed this special characteristic of silicon and invented the microchip.