Wide band gap semiconductors
Semiconductors with a wide band gap ( English wide-bandgap semiconductors , derived from wide-bandgap semiconductors but broadband semiconductors ) are semiconductors whose band gap (energy gap between valence band and conduction band ) is at the upper end of the semiconductor range (3 eV to over 4 eV ) lies.
Properties and uses
The properties of semiconductor materials are mainly determined by the energetic distance between the valence band and the conduction band. Electrical conductors do not have a band gap, while the band gap in the case of non-conductors is greater than 4 eV. In the case of the semiconductors that have been mostly used up to now, the band gap is in the lower range. B. for germanium (Ge) at 0.67 eV, for silicon (Si) at 1.12 eV and for gallium arsenide (GaAs) at 1.42 eV. In the case of wide band gap semiconductors, the band gap is greater than 3 eV.
Because of the excellent properties of silicon in the production of semiconductor circuits and their applications, most electronic circuits are based on silicon as a semiconductor material. For special requirements such as B. for low-noise amplifiers and high-frequency amplifiers in cell phones and satellite communication , the compound semiconductor GaAs is often used. GaN components are increasingly being used in high-frequency power amplifiers in cellular network infrastructure.
The use of wide bandgap materials offers further advantages:
- Lower losses with switching regulators
- Processing of higher voltages
- Operation at higher (ambient) temperatures
- Processing of higher frequencies
- Greater reliability
In addition to these circuit-related properties, the high band gap enables the effective emission of shorter-wave (visible) light and thus, for example, light-emitting diodes (LEDs) with the colors blue or ultraviolet .
There are some disadvantages to the further spread of the materials: In addition to being able to be manufactured on an industrial scale at reasonable manufacturing costs, development tools must support the material properties and new housing technologies allow use at possibly higher operating temperatures. In contrast to silicon technology, wide-bandgap semiconductors for power components usually have to be applied to substrates made of other (easier to manufacture) materials: GaN on sapphire or SiC , SiC and diamond on silicon.
Representative
| material | Band gap in eV (at 300 K) |
|---|---|
| IV-IV compound semiconductors | |
| SiC | 3.03 |
| III-V compound semiconductors | |
| GaN | 3.37 |
| InGaN | 0.7-3.37 |
| BN | 5.8 |
| AlN | 6.2 |
| II-VI compound semiconductors | |
| ZnO | 3.37 |
| element | |
| C (as diamond ) | 5.46-5.6 |
Band gaps in the corresponding energy range can be found e.g. B. with elemental carbon in the modification as diamond . One possible combination of elements from group IV of the periodic table is silicon carbide . From the field of compound semiconductors, there are various suitable combinations such as gallium nitride (III-V) and zinc oxide (II-VI). Corresponding compound semiconductors with more than two elements such as B. indium gallium nitride (InGaN) are possible materials. Here even the band gap can be adjusted by the ratio of indium nitride to gallium nitride.
market
According to the Taiwanese electronics daily DigiTimes, the market for silicon-based power semiconductors was greater than US $ 24 billion in 2016. In the same year, SiC and GaN only sold $ 200 million and $ 14 million, respectively, although higher growth rates are expected for compound semiconductors in the future. SiC will primarily replace silicon in high-performance applications and GaN in medium-performance ranges.
Individual evidence
- ↑ Werner Bindmann: German Dictionary of Microelectronics. Psychology Press, 1999, ISBN 0-415-17340-X , p. 478 ( limited preview in Google book search).
- ^ A b Dimitris Pavlidis: Wide- and Narrow-Bandgap Semiconductor Materials. (PDF) In: Topic Research. TU-Darmstadt , February 2006, pp. 38–41 , accessed on June 5, 2015 (English, German).
- ^ AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 101st edition. Walter de Gruyter, Berlin 1995, ISBN 3-11-012641-9 , p. 1313.
- ↑ Shyh-Chiang Shen: Wide-bandgap device research and development at SRL. Georgia Institute of Technology Semiconductor Research Laboratory, accessed June 5, 2015 .
- ↑ Diana Goovaerts: GaN Gaining Ground in Mobile Wireless Infrastructure Market. Wireless Week, March 27, 2017, accessed April 1, 2017 .
- ^ A b Wide Bandgap Semiconductors: Pursuing the Promise. (PDF) (No longer available online.) United States Department of Energy , April 2013, archived from the original on February 22, 2016 ; accessed on June 5, 2015 .
- ↑ SiC use in automotive drive converters. (PDF) Uni Bayreuth , accessed on March 1, 2017 .
- ^ Adam Khan: Not-So Quiet Race in Wide Band Gap Semiconductor. EE Times , June 30, 2016, accessed July 4, 2016 .
- ↑ Chris JH Wort, Richard S. Balmer: Diamond as an electronic material. In: ScienceDirect, Volume 11, Issues 1–2, January – February 2008. Elsevier, January 7, 2008, pp. 22–28 , accessed on August 13, 2017 (English).
- ↑ Ricky Tu: Digitimes Research: SiC, GaN power semiconductor markets to grow fast through 2025. DigiTimes , November 30, 2017, accessed on November 30, 2017 (English).