Manufacturing Bits: Feb. 16

Monoxide chips; hard nanocomposite materials; making GaN.


Monoxide chips
Two-dimensional (2D) materials are gaining steam in the R&D labs. The 2D materials could enable a new class of field-effect transistors (FETs), but the technology isn’t expected to appear until sometime in the next decade.

The 2D materials include graphene, boron nitride and the transition-metal dichalcogenides (TMDs). One TMD, molybdenum diselenide (MoS2), is gaining interest in the market.

The University of Utah, meanwhile, has discovered a new 2D material–tin monoxide (SnO). SnO combines tin and oxygen. In the lab, researchers devised a SnO field effect transistor (FET).

To date, graphene, MoS2 and other 2D materials only allow the movement of N-type, or negative, electrons, according to researchers from the University of Utah. SnO is the world’s first stable P-type 2D material, according to researchers.

This, in turn, could accelerate the development of 2D-based FETs in the market. “Now we have everything—we have P-type 2D semiconductors and N-type 2D semiconductors,” said Ashutosh Tiwari, a materials science and engineering associate professor at the University of Utah in a statement. “Now things will move forward much more quickly.”

In the lab, researchers started with a silicon substrate. Then, they formed SnO material layer-by-layer using a pulsed laser deposition technology. As a result, FETs with SnO channels were fabricated. These FETs showed p-channel conduction, with mobilities ranging from 0.05 to 1.9 cm2 V−1 s−1.

New and hard nanocomposite materials
The Hamburg University of Technology, the University of Hamburg, the Helmholtz Centre Geesthacht and DESY have synthesized a new and extremely hard nanocomposite material.

The materials are based on iron oxide nanoparticles in super crystal structures. These materials could be used for filling dental cavities, manufacturing watch cases and other applications.

Researchers devised a self-assembly manufacturing technique. In the flow, ceramic iron oxide nanoparticles are deposited in a regular array. This is done using organic oleic acid. The acid seeps into the narrow gaps between the nanoparticles. This, in turn, holds them together

Image of the iron oxide nanoparticles, immersed in oleic acid. (Credit: TUHH)

Image of the iron oxide nanoparticles, immersed in oleic acid. (Credit: TUHH)

With the process, researchers devised nearly spherical iron oxide nanoparticles in super crystals. This, in turn, led to the development of a nanocomposite with bending modulus of 114 GPa, a hardness of up to 4 GPa, and a strength of up to 630 MPa, according to researchers.

The bonding properties of the oleic acid serve as an adhesive. The bonding process was observed using a spectroscopic system at the Deutsches Elektronen-Synchrotron, a Research Centre of the Helmholtz Association. “Our measurements showed that the oleic acid molecules survive the thermal treatment and form additional crosslinks during the process,” said Andreas Stierle, a scientist at DESY, on the agency’s Web site. “This important finding can serve as the basis for successfully modeling the mechanical properties of this novel material.”

Ultra-high vacuum chamber at the DESY-NanoLab, in which the spectroscopic analysis was carried out. (Credit: DESY, Heiner Müller-Elsner)

Ultra-high vacuum chamber at the DESY-NanoLab, in which the spectroscopic analysis was carried out. (Credit: DESY, Heiner Müller-Elsner)

Making GaN
Veeco Instruments has signed a joint development project agreement with Imec.

The collaboration is expected to accelerate the development of highly-efficient, gallium nitride (GaN) based, power electronic devices using GaN epi wafers. This is created using Veeco’s Propel Power GaN MOCVD system. Imec has already demonstrated gains in GaN layer uniformity and run-to-run repeatability with Veeco’s Propel system, resulting in improved power device yields.

“Within the framework of our industrial affiliation program on GaN-on-Si, Veeco and Imec have collaborated over the last four years to improve the epi quality of GaN layers deposited on silicon wafer substrates,” said Rudi Cartuyvels, senior vice president of smart systems and energy technologies at Imec. “The ultimate goal is to produce the next-generation of highly-efficient power switching devices. We have set very high GaN device yield and reliability targets for 2016 and we look forward to partnering with Veeco to achieve these targets.”

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