Semiconductors: The Silicon Chip Essay examples -- science

Semiconductors The atomic number 14 ChipSilicon is the raw material most often used in compound circuit (IC) fabrication. It is the second most superabundant substance on the earth. It is extracted from rocks and common beach sand and put through an exhaustive purification process. In this form, ti is the purist industrial substance that man produces, with impurities comprising less(prenominal) than one part in a billion. That is the equivalent of one tennis ball in a get out of golf balls stretching from the earth to the moon. Semiconductors be usually materials which have energy-band gaps smaller than 2eV. An important property of semiconductor devices is the ability to change their resistivity over several orders of magnitude by doping. Semiconductors have galvanizing resistivities amidst 10-5 and 107 ohms. Semiconductors can be crystalline or amorphous. Elemental semiconductors are simple-element semiconductor materials such as atomic number 14 or germanium. Silicon is t he 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 cuboidal structure. Silicon is conventionally doped with Phosphorus, ratsbane 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. at once I will give you slightly brief history of the evolution of electronics which will help you understand more about semiconductors and the silicon chip. In the primeval 1900s 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 red-hot 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 period to warm up, got very hot, and eventually burned out. The first digital computer c... ..., the second mask pattern is unfastened 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 constrain a particular IC. Of critical greatness here is the precise alignment of each mask over the wafer surface. It is out of alignment more than a figure of a micrometer (one-millionth of a meter), the built-in wafer is useless. During the last diffusion a bed of oxide is again grown over the water. Most of this oxide layer is left on the wa fer to serve as an electrical insulator, and solely small openings are etched through the oxide to expose circuit contact areas. To interconnect these areas, a thin layer of admixture (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 interconnectedness pattern between the circuit elements. The last(a) 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 soldering pads, the square aluminum areas to which wires will by and by be attached. Semiconductors The Silicon Chip Essay examples -- scienceSemiconductors The Silicon ChipSilicon 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 throu gh 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 variet y 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 1900s 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 bu lky, 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... ..., 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. Mos t 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.