Flexible silicon

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Flexible silicon refers to a flexible piece of mono-crystalline silicon. Several processes have been demonstrated in the literature for obtaining flexible silicon from single crystal silicon wafers (either before or after fabrication of CMOS circuits). [1]

Contents

Background

According to beam theory and the 3-point test of a rectangular beam of an istoroptic linear material, a perpendicular specific force applied to a rectangular beam would cause it to deflect as a function of its dimension parameters and material properties (i.e. flexural modulus). All parameters fixed, the dependence of the deflection on thickness is inversely proportional, i.e. the thinner the beam the more it deflects when the same force is applied. In a simplistic manner, the applied force per unit area is the stress experienced by the beam. For two beams made of similar materials but one is thinner than the other, a lower force (stress) is required to achieve the same deflection in the thinner beam. This opens up a possibility of reducing a beam's thickness to adjust the amount of stress it can handle before physically breaking, if deflection requirement is the same. Applying this concept on the commonly used brittle Monocrystalline silicon (100) substrates, it can achieve some flexibility (note that silicon is an anisotropic material and requires dealing with elasticity matrix, a tensor, not a simple value for flexural modulus). This is done by using various micro-fabrication techniques and novel approaches to reduce the silicon substrate thickness to few to tens of micrometers, enabling bending up to 0.5 cm radius without breaking.

Processes

Etch protect release approach and backside etch are few examples of how this can be achieved. These techniques have been extensively used to demonstrate flexible versions of traditional high-performance CMOS compatible devices, including 3D fin-field effect transistors (finFETs) [2] [3] and planar metal–oxide–semiconductor FETs (MOSFETs), [4] metal-oxide semiconductor/metal-insulator-metal capacitors (MOSCAPs and MIMCAPs), [5] [6] [7] ferroelectric capacitors and resistive devices, [8] [9] [10] [11] and thermoelectric generators (TEGs). [12]

Related Research Articles

<span class="mw-page-title-main">Integrated circuit</span> Electronic circuit formed on a small, flat piece of semiconductor material

An integrated circuit or monolithic integrated circuit is a set of electronic circuits on one small flat piece of semiconductor material, usually silicon. Large numbers of tiny MOSFETs integrate into a small chip. This results in circuits that are orders of magnitude smaller, faster, and less expensive than those constructed of discrete electronic components. The IC's mass production capability, reliability, and building-block approach to integrated circuit design has ensured the rapid adoption of standardized ICs in place of designs using discrete transistors. ICs are now used in virtually all electronic equipment and have revolutionized the world of electronics. Computers, mobile phones and other home appliances are now inextricable parts of the structure of modern societies, made possible by the small size and low cost of ICs such as modern computer processors and microcontrollers.

<span class="mw-page-title-main">Transistor</span> Solid-state electrically operated switch also used as an amplifier

A transistor is a semiconductor device used to amplify or switch electrical signals and power. The transistor is one of the basic building blocks of modern electronics. It is composed of semiconductor material, usually with at least three terminals for connection to an electronic circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Some transistors are packaged individually, but many more in miniature form are found embedded in integrated circuits.

<span class="mw-page-title-main">MOSFET</span> Type of field-effect transistor

The metal–oxide–semiconductor field-effect transistor is a type of field-effect transistor (FET), most commonly fabricated by the controlled oxidation of silicon. It has an insulated gate, the voltage of which determines the conductivity of the device. This ability to change conductivity with the amount of applied voltage can be used for amplifying or switching electronic signals. A metal-insulator-semiconductor field-effect transistor (MISFET) is a term almost synonymous with MOSFET. Another synonym is IGFET for insulated-gate field-effect transistor.

<span class="mw-page-title-main">CMOS</span> Technology for constructing integrated circuits

Complementary metal–oxide–semiconductor is a type of metal–oxide–semiconductor field-effect transistor (MOSFET) fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSFETs for logic functions. CMOS technology is used for constructing integrated circuit (IC) chips, including microprocessors, microcontrollers, memory chips, and other digital logic circuits. CMOS technology is also used for analog circuits such as image sensors, data converters, RF circuits, and highly integrated transceivers for many types of communication.

A thin-film transistor (TFT) is a special type of field-effect transistor (FET) where the transistor is thin relative to the plane of the device. TFTs are grown on a supporting substrate. A common substrate is glass, because the traditional application of TFTs is in liquid-crystal displays (LCDs). This differs from the conventional bulk metal oxide field effect transistor (MOSFET), where the semiconductor material typically is the substrate, such as a silicon wafer.

Bipolar CMOS (BiCMOS) is a semiconductor technology that integrates two semiconductor technologies, those of the bipolar junction transistor and the CMOS logic gate, into a single integrated circuit. In more recent times the bipolar processes have been extended to include high mobility devices using silicon–germanium junctions.

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<span class="mw-page-title-main">Fin field-effect transistor</span> Type of non-planar transistor

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<span class="mw-page-title-main">Organic field-effect transistor</span> Type of field-effect transistor

An organic field-effect transistor (OFET) is a field-effect transistor using an organic semiconductor in its channel. OFETs can be prepared either by vacuum evaporation of small molecules, by solution-casting of polymers or small molecules, or by mechanical transfer of a peeled single-crystalline organic layer onto a substrate. These devices have been developed to realize low-cost, large-area electronic products and biodegradable electronics. OFETs have been fabricated with various device geometries. The most commonly used device geometry is bottom gate with top drain and source electrodes, because this geometry is similar to the thin-film silicon transistor (TFT) using thermally grown SiO2 as gate dielectric. Organic polymers, such as poly(methyl-methacrylate) (PMMA), can also be used as dielectric. One of the benefits of OFETs, especially compared with inorganic TFTs, is their unprecedented physical flexibility, which leads to biocompatible applications, for instance in the future health care industry of personalized biomedicines and bioelectronics.

Deep reactive-ion etching (DRIE) is a highly anisotropic etch process used to create deep penetration, steep-sided holes and trenches in wafers/substrates, typically with high aspect ratios. It was developed for microelectromechanical systems (MEMS), which require these features, but is also used to excavate trenches for high-density capacitors for DRAM and more recently for creating through silicon vias (TSVs) in advanced 3D wafer level packaging technology. In DRIE, the substrate is placed inside a reactor, and several gases are introduced. A plasma is struck in the gas mixture which breaks the gas molecules into ions. The ions accelerated towards, and react with the surface of the material being etched, forming another gaseous element. This is known as the chemical part of the reactive ion etching. There is also a physical part, if ions have enough energy, they can knock atoms out of the material to be etched without chemical reaction.

<span class="mw-page-title-main">Hafnium(IV) oxide</span> Chemical compound

Hafnium(IV) oxide is the inorganic compound with the formula HfO
2. Also known as hafnium dioxide or hafnia, this colourless solid is one of the most common and stable compounds of hafnium. It is an electrical insulator with a band gap of 5.3~5.7 eV. Hafnium dioxide is an intermediate in some processes that give hafnium metal.

Ghavam G. Shahidi is an Iranian-American electrical engineer and IBM Fellow. He is the director of Silicon Technology at the IBM Thomas J Watson Research Center. He is best known for his pioneering work in silicon-on-insulator (SOI) complementary metal–oxide–semiconductor (CMOS) technology since the late 1980s.

<span class="mw-page-title-main">MIS capacitor</span>

A MIS capacitor is a capacitor formed from a layer of metal, a layer of insulating material and a layer of semiconductor material. It gets its name from the initials of the metal-insulator-semiconductor (MIS) structure. As with the MOS field-effect transistor structure, for historical reasons, this layer is also often referred to as a MOS capacitor, but this specifically refers to an oxide insulator material.

<span class="mw-page-title-main">Mohamed M. Atalla</span> Egyptian engineer, physicist, cryptographer, inventor and entrepreneur

Mohamed M. Atalla was an Egyptian-American engineer, physicist, cryptographer, inventor and entrepreneur. He was a semiconductor pioneer who made important contributions to modern electronics. He is best known for inventing the MOSFET in 1959, which along with Atalla's earlier surface passivation and thermal oxidation processes, revolutionized the electronics industry. He is also known as the founder of the data security company Atalla Corporation, founded in 1972. He received the Stuart Ballantine Medal and was inducted into the National Inventors Hall of Fame for his important contributions to semiconductor technology as well as data security.

<span class="mw-page-title-main">Field-effect transistor</span> Type of transistor

The field-effect transistor (FET) is a type of transistor that uses an electric field to control the flow of current in a semiconductor. FETs are devices with three terminals: source, gate, and drain. FETs control the flow of current by the application of a voltage to the gate, which in turn alters the conductivity between the drain and source.

<span class="mw-page-title-main">Silicon-tin</span>

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<span class="mw-page-title-main">Muhammad M. Hussain</span>

Muhammad Mustafa Hussain is an electronics engineer specializing in CMOS technology-enabled low-cost flexible, stretchable and reconfigurable electronic systems. He is a professor in King Abdullah University of Science and Technology. He is the principal investigator (PI) at Integrated Nanotechnology Laboratory, and Integrated Disruptive Electronic Applications (IDEA) Laboratory. He is also the director of the Virtual Fab: vFabLab™.

A ferroelectric field-effect transistor is a type of field-effect transistor that includes a ferroelectric material sandwiched between the gate electrode and source-drain conduction region of the device. Permanent electrical field polarisation in the ferroelectric causes this type of device to retain the transistor's state in the absence of any electrical bias.

<span class="mw-page-title-main">MOSFET applications</span>

The metal–oxide–semiconductor field-effect transistor, also known as the metal–oxide–silicon transistor, is a type of insulated-gate field-effect transistor (IGFET) that is fabricated by the controlled oxidation of a semiconductor, typically silicon. The voltage of the covered gate determines the electrical conductivity of the device; this ability to change conductivity with the amount of applied voltage can be used for amplifying or switching electronic signals.

References

  1. ↑ Hussain, Aftab M.; Hussain, Muhammad M. (June 2016). "CMOS-Technology-Enabled Flexible and Stretchable Electronics for Internet of Everything Applications". Advanced Materials. 28 (22): 4219–4249. doi:10.1002/adma.201504236. PMID   26607553. S2CID   28740742.
  2. ↑ Ghoneim, Mohamed; Alfaraj, Nasir; Torres-Sevilla, Galo; Fahad, Hossain; Hussain, Muhammad (July 2016). "Out-of-Plane Strain Effects on Physically Flexible FinFET CMOS". IEEE Transactions on Electron Devices. 63 (7): 2657–2664. Bibcode:2016ITED...63.2657G. doi:10.1109/TED.2016.2561239. hdl: 10754/610712 . S2CID   26592108.
  3. ↑ Torres Sevilla, Galo A; Ghoneim, Mohamed T; Fahad, Hossain; Rojas, Jhonathan P; Hussain, Aftab M; Hussain, Muhammad M (5 September 2014). "Flexible nanoscale high-performance FinFETs". ACS Nano. 8 (10): 9850–6. doi:10.1021/nn5041608. PMID   25185112.
  4. ↑ Rojas, Jhonathan P; Torres Sevilla, Galo A; Hussain, Muhammad M (10 September 2013). "Can we build a truly high performance computer which is flexible and transparent?". Scientific Reports. 3: 2609. Bibcode:2013NatSR...3E2609R. doi:10.1038/srep02609. PMC   3767948 . PMID   24018904.
  5. ↑ Ghoneim, Mohamed T.; Rojas, Jhonathan P.; Young, Chadwin D.; Bersuker, Gennadi; Hussain, Muhammad M. (26 November 2014). "Electrical Analysis of High Dielectric Constant Insulator and Metal Gate Metal Oxide Semiconductor Capacitors on Flexible Bulk Mono-Crystalline Silicon". IEEE Transactions on Reliability. 64 (2): 579–585. doi:10.1109/TR.2014.2371054. S2CID   11483790.
  6. ↑ Ghoneim, Mohamed T.; Kutbee, Arwa; Ghodsi, Farzan; Bersuker, G.; Hussain, Muhammad M. (9 June 2014). "Mechanical anomaly impact on metal–oxide–semiconductor capacitors on flexible silicon fabric". Applied Physics Letters. 104 (23): 234104. Bibcode:2014ApPhL.104w4104G. doi:10.1063/1.4882647. hdl: 10754/552155 . S2CID   36842010.
  7. ↑ Rojas, Jhonathan P; Ghoneim, Mohamed T; Young, Chadwin D; Hussain, Muhammad M (October 2013). "Flexible High-k Metal Gate Metal/Insulator/Metal Capacitors on Silicon (100) Fabric". IEEE Transactions on Electron Devices. 60 (10): 3305–3309. doi:10.1109/TED.2013.2278186. S2CID   39246663.
  8. ↑ Ghoneim, Mohamed T.; Hussain, Muhammad M. (23 July 2015). "Review on physically flexible nonvolatile memory for internet of everything electronics". Electronics. 4 (3): 424–479. arXiv: 1606.08404 . doi: 10.3390/electronics4030424 .
  9. ↑ Ghoneim, Mohamed T.; Hussain, Muhammad M. (3 August 2015). "Study of harsh environment operation of flexible ferroelectric memory integrated with PZT and silicon fabric". Applied Physics Letters. 107 (5): 052904. Bibcode:2015ApPhL.107e2904G. doi:10.1063/1.4927913. hdl: 10754/565819 .
  10. ↑ Ghoneim, Mohamed T.; Zidan, Mohammed A.; Alnassar, Mohammed Y.; Hanna, Amir N.; Kosel, Jurgen; Salama, Khaled N.; Hussain, Muhammad (15 June 2015). "Flexible Electronics: Thin PZT-Based Ferroelectric Capacitors on Flexible Silicon for Nonvolatile Memory Applications". Advanced Electronic Materials. 1 (6): 1500045. doi:10.1002/aelm.201500045. S2CID   110038210.
  11. ↑ Ghoneim, Mohamed T; Zidan, Mohammed A; Salama, Khaled N; Hussain, Muhammad M (30 November 2014). "Towards neuromorphic electronics: Memristors on foldable silicon fabric". Microelectronics Journal. 45 (11): 1392–1395. doi:10.1016/j.mejo.2014.07.011.
  12. ↑ Torres Sevilla, Galo; Bin Inayat, Salman; Rojas, Jhonathan; Hussain, Aftab; Hussain, Muhammad (9 December 2013). "Flexible and Semi‐Transparent Thermoelectric Energy Harvesters from Low Cost Bulk Silicon (100)". Small. 9 (23): 3916–3921. doi:10.1002/smll.201301025. PMID   23836675.
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