Semiconductor Materials and Process Chemicals Vocabulary

A comprehensive vocabulary review set covering atomic structure, semiconductor electrical properties, doping mechanisms, engineered substrate technologies, and processing chemicals.

Bohr atom model

An atomic model in which positively charged protons and neutral neutrons reside together in the nucleus, surrounded by negatively charged electrons moving in defined orbits.

Atomic number

The number assigned to each element in the periodic table, equal to the number of protons (and therefore electrons) in its atom.

Orbit electron capacity rule

The rule stating that each electron orbit ($n$) can hold a maximum of $2n^2$ electrons.

Conductivity

The property of materials to conduct electricity by permitting a flow of electrons.

Resistivity

The reciprocal of conductivity ($\rho$), measuring a material's opposition to electrical current flow in $\Omega\text{-cm}$.

Dielectrics

Materials exhibiting a large attractive force between the nucleus and orbiting electrons, resulting in low conductivity and high resistivity to function as insulators.

Capacitor

An electrical device formed whenever a dielectric layer is sandwiched between two conductors to store electrical charges.

Low-k dielectrics

Low-capacitance dielectric materials required in semiconductor metal conduction systems.

High-k dielectrics

High-capacitance dielectric materials used as insulators between conducting layers.

Intrinsic semiconductor

A semiconducting material in its purified state that is not contaminated with purposely added dopant impurities.

Doping

The process of introducing specific elements into an intrinsic semiconductor material to change and control its electrical properties.

Carrier concentration

The concentration of charge carriers (electrons or holes) present in a semiconductor material.

Hole

An unfilled position in an outer electron ring created when a dopant atom borrowing electrons lacks a full complement of eight.

Hole flow

A conduction mechanism unique to semiconducting materials where electrons sequentially jump into adjacent holes toward a positive pole, producing an apparent positive current moving in the opposite direction.

Donors

Column V dopant elements (such as arsenic, phosphorus, and antimony) that supply extra electrons to create N-type conditions in silicon.

Acceptors

Column III dopant elements (such as boron) that create unfilled electron positions to yield P-type conductivity in silicon.

Carrier mobility

The speed at which charge carriers (holes or electrons) move through a semiconducting material.

Radiation hardened

The characteristic of devices or materials (such as GaAs) that naturally resist radiation-caused leakage and remain functional in high-radiation environments.

Strained silicon

A structure where silicon atoms deposited on a silicon-germanium layer stretch to align with the wider-spaced Si/Ge atoms, lowering resistance and enabling electrons to move up to 70 percent faster.

Ferroelectric random access memories (FeRAMs)

Memory circuits that incorporate ferroelectric material capacitors such as $\text{PbZr}_{1-x}\text{T}_x\text{O}_3$ (PZT) and $\text{SrBi}_2\text{Ta}_2\text{O}_9$ (SBT) into SiCMOS structures.

Diatomic molecule

A molecule composed of two atoms of the same element, such as $O_2$, $N_2$, and $H_2$.

Slurry

A mixture subtype combining undissolved solid particles suspended in a liquid, commonly used in polishing processes such as chemical mechanical polishing (CMP).

Ion

Any atom or molecule that exists with an unbalanced electrical charge due to a loss or gain of electrons.

Plasma state

The fourth state of nature, defined as a high-energy collection of ionized atoms or molecules.

Kelvin scale

A absolute temperature scale based on theoretical absolute zero ($-273\,^\circ\text{C}$), where water freezes at $273\,\text{K}$ and boils at $373\,\text{K}$.

Specific gravity

The ratio of the density of a liquid or gas compared to that of water at $4\,^\circ\text{C}$.

Vapor density

A density measurement of gases under specific temperature and pressure conditions referenced against air, which is assigned a value of 1.

Torr

A unit of vacuum pressure defined as the equivalent force required to raise mercury $1\,\text{mm}$ in a manometer.

Acids

Liquids containing positively charged hydrogen ions ($\text{H}^+$) with pH values below 7.

Alkalis

Liquids (also called bases) containing negatively charged hydroxide ions ($\text{OH}^-$) with pH values greater than 7.

Solvents

Non-ionizing liquids that register neutral (pH 7) on the pH scale and are used to dissolve other substances.

Material Safety Data Sheet (MSDS)

An OSHA Form 20 document supplied with chemicals that outlines safety, health, chemical properties, storage, first aid, and usage information.