Hubbry Logo
Solid-state electronicsSolid-state electronicsMain
Open search
Solid-state electronics
Community hub
Solid-state electronics
logo
8 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Solid-state electronics
Solid-state electronics
Solid-state electronics
View on Wikipedia
from Wikipedia
An integrated circuit (IC) on a printed circuit board. This is called a solid-state circuit because all of the electrical activity in the circuit occurs within solid materials.

Solid-state electronics are semiconductor electronics: electronic equipment that use semiconductor devices such as transistors, diodes and integrated circuits (ICs).[1][2][3][4][5] The term is also used as an adjective for devices in which semiconductor electronics that have no moving parts replace devices with moving parts, such as the solid-state relay, in which transistor switches are used in place of a moving-arm electromechanical relay, or the solid-state drive (SSD), a type of semiconductor memory used in computers to replace hard disk drives, which store data on a rotating disk.[6]

History

[edit]

The term solid-state became popular at the beginning of the semiconductor era in the 1960s to distinguish this new technology. A semiconductor device works by controlling an electric current consisting of electrons or holes moving within a solid crystalline piece of semiconducting material such as silicon, while the thermionic vacuum tubes it replaced worked by controlling a current of electrons or ions in a vacuum within a sealed tube.

Although the first solid-state electronic device was the cat's whisker detector, a crude semiconductor diode invented around 1904, solid-state electronics started with the invention of the transistor in 1947.[7] Before that, all electronic equipment used vacuum tubes, because vacuum tubes were the only electronic components that could amplify—an essential capability in all electronics. The transistor, which was invented by John Bardeen and Walter Houser Brattain while working under William Shockley at Bell Laboratories in 1947,[8] could also amplify, and replaced vacuum tubes. The first transistor hi-fi system was developed by engineers at GE and demonstrated at the University of Philadelphia in 1955.[9] In terms of commercial production, The Fisher TR-1 was the first "all transistor" preamplifier, which became available mid-1956.[10] In 1961, a company named Transis-tronics released a solid-state amplifier, the TEC S-15.[11]

The replacement of bulky, fragile, energy-hungry vacuum tubes by transistors in the 1960s and 1970s created a revolution not just in technology but in people's habits, making possible the first truly portable consumer electronics such as the transistor radio, cassette tape player, walkie-talkie and quartz watch, as well as the first practical computers and mobile phones. Other examples of solid state electronic devices are the microprocessor chip, LED lamp, solar cell, charge coupled device (CCD) image sensor used in cameras, and semiconductor laser.

Also during the 1960s and 1970s, television set manufacturers switched from vacuum tubes to semiconductors, and advertised sets as "100% solid state"[12] even though the cathode-ray tube (CRT) was still a vacuum tube. It meant only the chassis was 100% solid-state, not including the CRT. Early advertisements spelled out this distinction,[13] but later advertisements assumed the audience had already been educated about it and shortened it to just "100% solid state". LED displays can be said to be truly 100% solid-state.[14]

See also

[edit]

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Solid-state electronics

View on Grokipedia
from Grokipedia
Solid-state electronics refers to the field of electronics that utilizes materials, such as or , to create devices and circuits that control the flow of electrical current without relying on or vacuum tubes, enabling compact, reliable, and efficient operation through components like diodes, transistors, and integrated circuits. This technology emerged as a revolutionary alternative to earlier vacuum-tube-based systems, fundamentally transforming computing, communication, and by allowing and increased performance. The history of solid-state electronics traces back to early 19th-century discoveries of properties, such as Michael Faraday's 1833 observation that the resistance of decreases with temperature, and Karl Ferdinand Braun's 1874 identification of rectification in metal sulfides. A pivotal milestone occurred in 1947 when and Walter Brattain, under William Shockley's leadership at Bell Laboratories, invented the using , followed by Shockley's 1948 development of the junction transistor. This breakthrough, awarded the 1956 , replaced bulky vacuum tubes and paved the way for integrated circuits, with demonstrating the first IC in 1958 at . Key components in solid-state electronics include diodes, which permit current flow in one direction and are essential for rectification and ; bipolar junction transistors (BJTs), which amplify or switch signals using both electrons and holes as charge carriers; and field-effect transistors (FETs), such as MOSFETs, which provide voltage-controlled operation with high . These elements form the basis of integrated circuits (ICs), where billions of transistors are fabricated on a single chip, enabling complex functionalities like and logic operations. Applications span modern devices, including smartphones, computers, solar cells, LEDs for lighting, and systems in electric vehicles, driving advancements in energy efficiency and computational power.

Fundamentals

Semiconductor Materials

Semiconductors are materials whose electrical conductivity falls between that of conductors and insulators, arising from an electronic band structure that permits partial thermal excitation of electrons across a moderate energy gap. This band gap typically ranges from about 0.5 to 3 eV, distinguishing semiconductors from metals (no gap) and insulators (large gap >5 eV). Prominent examples include the elemental semiconductors silicon (Si) and germanium (Ge), as well as the III-V compound semiconductor gallium arsenide (GaAs). At 300 K, silicon exhibits a band gap of 1.12 eV, germanium 0.67 eV, and gallium arsenide 1.42 eV. The atomic in these materials forms ordered lattices that underpin their electronic properties and conductivity mechanisms. and both adopt the lattice structure, consisting of a face-centered cubic with a two-atom basis, where each atom is covalently bonded to four neighbors in a tetrahedral configuration. This structure yields an indirect , requiring interactions for transitions and influencing and electrical conductivity through the resulting band dispersion. In contrast, gallium forms the zincblende lattice, a variant of the structure with alternating gallium and atoms, which produces a direct and enhances radiative recombination efficiency. Semiconductors are categorized as intrinsic or extrinsic depending on their purity and carrier generation. Intrinsic semiconductors, like undoped , rely on alone to generate equal numbers of electrons and holes, with the intrinsic carrier concentration given by ni≈1010 cm−3n_i \approx 10^{10} \, \mathrm{cm}^{-3} at (300 K). This low carrier density reflects the energy required to bridge the band gap without external influences. Extrinsic semiconductors, formed by intentional impurity addition (doping), deviate from this balance to achieve higher conductivity tailored for devices. Central to semiconductor behavior is band theory, which models energy states as continuous bands rather than discrete atomic levels. The valence band represents the range of energies for bound s forming interatomic bonds, fully occupied at low temperatures. The conduction band, separated by the band gap EgE_g, encompasses energies where s are unbound and mobile, contributing to current flow upon population. The , the energy at which the probability of occupancy is 50% per the Fermi-Dirac distribution, lies midway in the band gap for intrinsic semiconductors at . This positioning ensures low intrinsic conductivity while allowing tunability through temperature or composition.

Charge Carriers and Doping

In solid-state electronics, charge carriers are the mobile particles responsible for electrical conduction in semiconductors. Electrons, which carry a negative charge, occupy the conduction band above the band gap, while holes, which behave as positive charge carriers due to the absence of an electron in the valence band, enable conduction through collective electron movement. In , the μ_n is approximately 1400 cm²/V·s at , allowing electrons to drift faster under an compared to holes, whose mobility μ_p is about 450 cm²/V·s. These mobility values reflect the ease with which carriers respond to fields, with electrons generally exhibiting higher mobility due to their lighter effective mass in the conduction band. Doping introduces controlled impurities to generate excess charge carriers, altering the semiconductor's electrical properties. In n-type doping, donor impurities such as (from group V elements) are added, each contributing an extra to the conduction band upon , as phosphorus replaces a atom and its fifth is loosely bound. The for phosphorus donors in silicon is approximately 0.045 eV, low enough for near-complete ionization at . Conversely, p-type doping uses acceptor impurities like (from group III), which creates in the valence band by accepting an from the lattice, leaving a positively charged vacancy. Boron's acceptor in silicon is also about 0.045 eV, facilitating hole generation under typical operating conditions. In doped semiconductors, carrier concentrations determine conduction dominance. For n-type material at , assuming donor density N_D greatly exceeds the intrinsic carrier concentration n_i (typically ~10^{10} cm^{-3} in ), the concentration n approximates N_D as the majority carriers, while the minority hole concentration p is n_i² / N_D. In p-type material, holes are the majority carriers with p ≈ N_A (acceptor density), and s are minorities at n ≈ n_i² / N_A. These relations hold under and complete , ensuring majority carriers outnumber minorities by orders of magnitude. Doping shifts the Fermi level E_F, the energy reference for carrier occupancy. In n-type semiconductors, E_F moves toward the conduction band edge E_c; for non-degenerate cases (N_D << N_c, where N_c is the effective density of states in the conduction band, ~2.8 × 10^{19} cm^{-3} in silicon at 300 K), it is given by EF≈Ec−kTln⁡(NcND),E_F \approx E_c - kT \ln\left(\frac{N_c}{N_D}\right), where k is Boltzmann's constant and T is temperature, reflecting higher electron probability near E_c. At high doping levels where N_D approaches or exceeds N_c, the semiconductor becomes degenerate, with E_F entering the conduction band, leading to Pauli exclusion effects that modify carrier statistics beyond the Boltzmann approximation. This degeneracy enhances conductivity but can introduce quantum mechanical behaviors like band filling.

Key Devices

Diodes and Rectifiers

Diodes are fundamental two-terminal solid-state devices that allow current to flow more easily in one direction than the other, enabling rectification and other control functions in electronic circuits. The most common type is the p-n junction diode, formed by joining a p-type semiconductor, doped with acceptors like to create holes as majority carriers, to an n-type semiconductor, doped with donors like to provide electrons as majority carriers. Upon junction formation, electrons from the n-side diffuse to the p-side and holes from the p-side diffuse to the n-side, recombining and leaving behind immobile ionized dopants that create a depletion region—a charge-depleted zone devoid of free carriers. This region establishes a built-in electric field opposing further diffusion, with a built-in potential Vbi≈0.7 VV_{bi} \approx 0.7 \, \text{V} for at room temperature. The width of the depletion region, WW, varies with applied bias and is approximated for a one-sided abrupt junction under reverse bias as W≈2ε(Vbi+VR)qNA,W \approx \sqrt{\frac{2 \varepsilon (V_{bi} + V_R)}{q N_A}},
Add your contribution
Related Hubs
User Avatar
No comments yet.