SILICON-BASED SEMICONDUCTORS

Perfection especially is required on the silicon surface. A 100 surface of silicon contains 6.8 x 1014 atoms/cm2. Surface defect densities must be less than one part in 105—105 defects/cm2 for satisfactory MOSFET operation. In fact, the discovery of the original point contact transistor was only possible because the native oxide on single-crystal germanium has surface defect densities less than one part in 104. Good silicon devices required the discovery (10) that the thermal oxidation of silicon could produce an excellent Si—Si02 interface. 

The high purity required of silicon and the small size of semiconductor devices place stringent limits on the chemicals used in processing silicon. By far the most important chemical is water which is used extensively to dilute etchants and clean wafers. Pure water (24) is required to have fewer than 0.025 

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

Silicon is a Group 14 (IV) element of the Periodic Table. This column includes C, Si, Ge, Sn, and Pb and displays a remarkable transition from insulating to metallic behavior with increasing atomic weight. Carbon, in the form of diamond, is a transparent insulator, whereas tin and lead are metals in fact, they are superconductors. Silicon and germanium are semiconductors, ie, they look metallic, so that a polished silicon wafer is a reasonable gray-toned mirror, but they conduct poody. Traditionally, semiconductors have been defined as materials whose resistance rises with decreasing temperature, unlike metals whose resistance falls. 

Material Cubic lattice constant, pm Band gap, eV Intrinsic carrier concentration, cm-3 Relative dielectric constant, 8 Mobility, Electrons cm2/(Vs) Holes 

The pace of technological change ia both the microelectronics-based computer revolution, as characterized by the number of bits in a DRAM, and the industrial revolution, as characterized by the horsepower developed by a steam engine (19). 

---

SEMICONDUCTORS - SILICON-BASED SEMICONDUCTORS] (Vol 21) -gelatin in [GELATIN] (Vol 12)... 

Acceptor atoms, in silicon-based semiconductors, 22 236 Acceptor molecules... 

---