Semiconductor Technology from A to Z

Everything about semiconductors and wafer fabrication

1. The elements

An element consists of several identical atoms and is a substance that can not be further decomposed by chemical means. The mass of elements is determined only by the number of protons and neutrons, since the electron mass is negligible. Hydrogen with one proton and no neutron has the mass number 1, the next heavier element, helium, has the mass number 4 (2 protons + 2 neutrons).

The elements are usually named with the initials of their Latin or Greek names (from latin hydrogenium: hydrogen H, from greek lithos: lithium Li).

2. The periodic table of the chemical elements

The periodic table of the chemical elements (periodic table) lists all the chemical elements with increasing proton number (atomic number) and according to their chemical properties, divided into periods as well as main and subgroups.

The period represents the number of electron shells, the main group, the number of electrons in the outermost shell (1 to 8 electrons). Group 1 and 2 and 13-18 are the maingroups, the group of 3-12 the subgroups.

The first element with one shell (period 1) and one outer electron (group 1) is hydrogen H. The next element, helium He, has only one electron shell and is therefore in period 1 as well. Since the first shell is completely filled with only two electrons, helium is not in group 2, but in group 18 (group of the noble gases).

To add more electrons, one needs to begin a new electron shell. Thus we find lithium Li in group 1, period 2 (two electrons on the first shell, one valence electron on the second shell). A shell can hold a maximum of 2n2 electrons, where n stands for the period.

From the fourth period there exist the groups (3-12) of the transition elements. After the first two valence electrons were added in maingroup 1 and 2 to the outermost shell, more inner shells are filled in the transitional groups for energetic reasons, before the outer shell is completely filled with electrons in maingroup 13-18.

The periodic table of the elements

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
1 HElement 1: Wasserstoff (H), Nichtmetall HeElement 2: Helium (He), Edelgas
2 LiElement 3: Lithium (Li), Alkalimetall BeElement 4: Beryllium (Be), Erdalkalimetall BElement 5: Bor (B), Halbmetall CElement 6: Kohlenstoff (C), Nichtmetall NElement 7: Stickstoff (N), Nichtmetall OElement 8: Sauerstoff (O), Nichtmetall FElement 9: Fluor (F), Halogen NeElement 10: Neon (Ne), Edelgas
3 NaElement 11: Natrium (Na), Alkalimetall MgElement 12: Magnesium (Mg), Erdalkalimetall AlElement 13: Aluminium (Al), Metall SiElement 14: Silicium (Si), Halbmetall PElement 15: Phosphor (P), Nichtmetall SElement 16: Schwefel (S), Nichtmetall ClElement 17: Chlor (Cl), Halogen ArElement 18: Argon (Ar), Edelgas
4 KElement 19: Kalium (K), Alkalimetall CaElement 20: Calcium (Ca), Erdalkalimetall ScElement 21: Scandium (Sc), Übergangsmetall TiElement 22: Titan (Ti), Übergangsmetall VElement 23: Vanadium (V), Übergangsmetall CrElement 24: Chrom (Cr), Übergangsmetall MnElement 25: Mangan (Mn), Übergangsmetall FeElement 26: Eisen (Fe), Übergangsmetall CoElement 27: Cobalt (Co), Übergangsmetall NiElement 28: Nickel (Ni), Übergangsmetall CuElement 29: Kupfer (Cu), Übergangsmetall ZnElement 30: Zink (Zn), Übergangsmetall GaElement 31: Gallium (Ga), Metall GeElement 32: Germanium (Ge), Halbmetall AsElement 33: Arsen (As), Halbmetall SeElement 34: Selen (Se), Nichtmetall BrElement 35: Brom (Br), Halogen KrElement 36: Krypton (Kr), Edelgas
5 RbElement 37: Rubidium (Rb), Alkalimetall SrElement 38: Strontium (Sr), Erdalkalimetall YElement 39: Yttrium (Y), Übergangsmetall ZrElement 40: Zirkonium (Zr), Übergangsmetall NbElement 41: Niob (Nb), Übergangsmetall MoElement 42: Molybdän (Mo), Übergangsmetall TcElement 43: Technitium (Tc), Übergangsmetall RuElement 44: Ruthenium (Ru), Übergangsmetall RhElement 45: Rhodium (Rh), Übergangsmetall PdElement 46: Palladium (Pd), Übergangsmetall AgElement 47: Silber (Ag), Übergangsmetall CdElement 48: Cadmium (Cd), Übergangsmetall InElement 49: Indium (In), Metall SnElement 50: Zinn (Sn), Metall SbElement 51: Antimon (Sb), Halbmetall TeElement 52: Tellur (Te), Halbmetall IElement 53: Iod (I), Halogen XeElement 54: Xenon (Xe), Edelgas
6 CsElement 55: Cäsium (Cs), Alkalimetall BaElement 56: Barium (Ba), Erdalkalimetall LaElement 57: Lanthan (La), Übergangsmetall HfElement 72: Hafnium (Hf), Übergangsmetall TaElement 73: Tantal (Ta), Übergangsmetall WElement 74: Wolfram (W), Übergangsmetall ReElement 75: Rhenium (Re), Übergangsmetall OsElement 76: Osmium (Os), Übergangsmetall IrElement 77: Iridium (Ir), Übergangsmetall PtElement 78: Platin (Pt), Übergangsmetall AuElement 79: Gold (Au), Übergangsmetall HgElement 80: Quecksilber (Hg), Übergangsmetall TlElement 81: Thallium (Tl), Metall PbElement 82: Blei (Pb), Metall BiElement 83: Bismuth (Bi), Metall PoElement 84: Polonium (Po), Halbmetall AtElement 85: Astat (At), Halogen RnElement 86: Radon (Rn), Edelgas
7 FrElement 87: Francium (Fr), Alkalimetall RaElement 88: Radium (Ra), Erdalkalimetall AcElement 89: Actinium (Ac), Übergangsmetall RfElement 104: Rutherfordium (Rf), Übergangsmetall DbElement 105: Dubnium (Db), Übergangsmetall SgElement 106: Seaborgium (Sg), Übergangsmetall BhElement 107: Bohrium (Bh), Übergangsmetall HsElement 108: Hassium (Hs), Übergangsmetall MtElement 109: Meitnerium (Mt), Übergangsmetall DsElement 110: Darmstadtium (Ds), Übergangsmetall RgElement 111: Roentgenium (Rg), Übergangsmetall CnElement 112: Copernicium (Cn), Übergangsmetall UutElement 113: Ununtrium (Uut), Metall FlElement 114: Flerovium (Fl), Metall UupElement 115: Ununpentium (Uup), Metall LvElement 116: Livermorium (Lv), Metall UusElement 117: Ununseptium (Uus), UuoElement 118: Ununoctium (Uuo), Edelgas
CeElement 58: Cer (Ce), Lanthanoid PrElement 59: Praseodym (Pr), Lanthanoid NdElement 60: Neodym (Nd), Lanthanoid PmElement 61: Promethium (Pm), Lanthanoid SmElement 62: Samarium (Sm), Lanthanoid EuElement 63: Europium (Eu), Lanthanoid GdElement 64: Gadolinium (Gd), Lanthanoid TbElement 65: Terbium (Tb), Lanthanoid DyElement 66: Dysprosium (Dy), Lanthanoid HoElement 67: Holmium (Ho), Lanthanoid ErElement 68: Erbium (Er), Lanthanoid TmElement 69: Thulium (Tm), Lanthanoid YbElement 70: Ytterbium (Yb), Lanthanoid LuElement 71: Lutetium (Lu), Lanthanoid
ThElement 90: Thorium (Th), Actinoid PaElement 91: Protactinium (Pa), Actinoid UElement 92: Uran (U), Actinoid NpElement 93: Neptunium (Np), Actinoid PuElement 94: Plutonium (Pu), Actinoid AmElement 95: Americium (Am), Actinoid CmElement 96: Curium (Cm), Actinoid BkElement 97: Berkelium (Bk), Actinoid CfElement 98: Californium (Cf), Actinoid EsElement 99: Einsteinium (Es), Actinoid FmElement 100: Fermium (Fm), Actinoid MdElement 101: Mendelevium (Md), Actinoid NoElement 102: Nobelium (No), Actinoid LrElement 103: Lawrencium (Lr), Actinoid
Alkali metal Metal Halogen Lanthanide
Alk. earth metal Metalloid Noble gas Actinide
Transition metal Nonmetal

Important elements in the semiconductor industry

Element Particle Note
B: Boron 5p, 6n, 5e 3 valence electrons: used for p-doping of silicon
N: Nitrogen 7p, 7n, 7e Stable N2 molecule: inert gas, cover layer on top of the wafer
O: Oxygen 8p, 8n, 8e Very reactive: oxidation of silicon, insulating layers (SiO2)
F: Fluorine 9p, 10n, 9e Most reactive element: used for etching in combination with other elements (ie HF, CF4)
Si: Silicon 14p, 14n, 14e Bulk material in semiconductor industry
P: Phosphorus 15p, 16n, 15e 5 valence electrons: used for n-doping of silicon

Elements that occur on the left side in the periodic table are metals. These elements have an aspiration to donate valence electrons to achieve the noble gas configuration. On the right side there are the nonmetals, which are trying to accept additional electrons to achieve the noble gas configuration. In between there are the semimetals such as silicon and germanium.