Could UV Light Improve Semiconductor Integration?
NREL scientists suggest that application of UV illumination could improve the optical properties of semiconductor layers
Integrating different semiconductor materials into an epitaxial device structure offers additional degrees of freedom to select for optimal material properties in each layer. However, interfaces between materials with different valences (i.e. III-V, II-VI and IV semiconductors) can be difficult to form with high quality.
Now, a discovery by Kwangwook Park and Kirstin Alberi, at the US Energy Department's National Renewable Energy Laboratory (NREL), suggests that careful application of UV illumination may be used to improve the optical properties of these material layers.
Park and Alberi experimented with integrating a layer of zinc selenide (ZnSe) grown on top of a layer of GaAs using UV light to modify the interface between them. Their results are published in a paper 'Tailoring Heterovalent Interface Formation with Light' in Scientific Reports.
Using a 150-watt xenon lamp to illuminate the growth surface, Park and Alberi determined the mechanisms of light-stimulated interface formation by varying the light intensity and interface initiation conditions. They found the UV light altered the mixture of chemical bonds at the interface through photo-induced desorption of arsenic atoms on the GaAs surface, resulting in a greater percentage of bonds between gallium and selenium, which help to passivate the underlying GaAs layer. The illumination also allowed the ZnSe to be grown at lower temperatures to better regulate elemental intermixing at the interface.
"The real value of this work is that we now understand how light affects interface formation, which can guide researchers in integrating a variety of different semiconductors in the future," Park said.
The NREL scientists suggested careful application of UV illumination may be used to improve the optical properties of both layers.
The work was funded by DOE's Office of Science.
AngelTech Live III: Join us on 12 April 2021!
AngelTech Live III will be broadcast on 12 April 2021, 10am BST, rebroadcast on 14 April (10am CTT) and 16 April (10am PST)
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Thanks to the great diversity of the semiconductor industry, we are always chasing new markets and developing a range of exciting technologies.
2021 is no different. Over the last few months interest in deep-UV LEDs has rocketed, due to its capability to disinfect and sanitise areas and combat Covid-19. We shall consider a roadmap for this device, along with technologies for boosting its output.
We shall also look at microLEDs, a display with many wonderful attributes, identifying processes for handling the mass transfer of tiny emitters that hold the key to commercialisation of this technology.
We shall also discuss electrification of transportation, underpinned by wide bandgap power electronics and supported by blue lasers that are ideal for processing copper.
Additional areas we will cover include the development of GaN ICs, to improve the reach of power electronics; the great strides that have been made with gallium oxide; and a look at new materials, such as cubic GaN and AlScN.
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