World’s first diamond nanoelectromechanical switch

Dec 24, 2010 By Mikiko Tanifuji
Fig. 1: Scanning electron microscope images of the suspended structures of single crystal diamond, (a) cantilever, (b) bridge, and (c) 3-terminal NEMS switch. Air gap structure has been formed in the substrate side.

Japanese researchers have succeeded in the batch fabrication of suspended structures (cantilevers and bridges) of single crystal diamond for nano/micro electromechanical systems.

Dr. Meiyong Liao, a Senior Researcher of Sensor Materials Center, National Institute for Materials Science, cooperated with his colleagues, succeeded in the batch fabrication of suspended structures (cantilevers and bridges) of single crystal diamond for nano/micro electromechanical systems (NEMS/MEMS). Based on this process, they achieved in the world the first single crystal diamond NEMS switch.

The NEMS switch has the advantages of low-leakage current, low-power consumption and sharp on/off ratio in comparison with the conventional semiconductor devices. Most of the existing NEMS/MEMS switches are based on silicon or metal materials, which have the drawbacks of poor mechanical, chemical, and thermal stability, poor reliability and durability. Diamond is the ideal material for NEMS/MEMS due to the highest elastic modulus, mechanical hardness, , and variable from insulator to conductor. However, due to the difficultly in fabricating suspended structures of single crystal diamond, the development of single crystal diamond NEMS/ has been a challenge.

The NIMS research team developed a process for fabricating suspended single crystal diamond structures by locally forming a graphite sacrificial layer in a single substrate by high energy , followed by the growth of a diamond epilayer with electrical conductivity by microwave plasma method (MPCVD) and the removal of the graphite sacrificial layer. As a further development of this technique, the group also succeeded for the first time in fabricating NEMS switching devices with a transistor-like structure comprising 3 electrodes.

The leakage current of the developed diamond NEMS switch is very low, and the is less than 10pW (picowatt). The devices exhibit high reproducibility, high reliability and no surface stiction. Stable operation of the diamond NEMS switch in a high temperature environment (250°C) was also confirmed. The Young’s modulus of the moveable cantilever structure was measured to be 1100GPa, which is close to the value of bulk diamond single crystals. Thus, high-speed (gigahertz) switching operation can be expected.

In comparison with the existing MEMS switches, the diamond NEMS switches are expected to show greatly improved functions, including reliability, lifetime, speed, and electrical handling capacity, etc. The developed devices can be applied as microwave switch for next-generation wireless communications and logic circuit under harsh environments. These research results also establish the infrastructure for diamond NEMS/MEMS with novel functions, opening the way for the development of various chemical, physical, and mechanical sensors.

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Provided by National Institute for Materials Science

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5 / 5 (2) Dec 24, 2010
If this thing had 6 stars they'd get it.

In credible.


Needs to be scaled down a tad, because this is still on the micrometer scale, but I think that should take care of itself as newer, smaller lasers are being invented.
1 / 5 (1) Dec 25, 2010
I don't understand why you would want this over a transistor switch.
not rated yet Dec 25, 2010
I don't understand why you would want this over a transistor switch.

I can only venture to guess that you have no background knowledge nor any basis for your statement. Thankyou for your contribution.
4.5 / 5 (2) Dec 25, 2010
I don't understand why you would want this over a transistor switch.

Imagine computers and sensors that can operate at 250C without being damaged.

this has applications in refining and manufacturing because you can put a diamond based sensor inside an injection molder or other hot environment, which will allow you to monitor your process to a degree of precision never before allowed.

Imagine a lunar rover or other spacecraft with sensors that can operate safely in direct exposure on the "daylight" side of the moon, wiht little or no thermal shielding.

Crystal computers could one day allow this.

Crystals are among the strongest materials known to man, so you could build a probe from crystal and have sensors built directly into structural crystal components.

Crystal is a 3d lattice, so one day it may also be possible to build 3-d computer architecture directly into the lattice by removing only the parts you don't want.