Advanced Computing Technologies: From Nanofabrication to Neuromorphic Systems

Advanced computing technologies are making great progress toward achieving high speed and low power consumption. Key advancements in this field include novel silicon architectures that use layered designs to build faster and smaller chips at a lower cost.

Advanced computing technologies are making great progress toward achieving high speed and low power consumption.

Key advancements in this field include novel silicon architectures that use layered designs to build faster and smaller chips at a lower cost. Meanwhile, photonic computing utilizes light waves to process and store data. With the speed of light simply unsurpassable, this can offer high speed and low latency.

Then, there is biological computing, where information is encoded and stored in biological cells, propelled by progress made in nanobiotechnology. Quantum computing also offers significant potential, solving complex problems faster than today's computers by leveraging quantum superposition, entanglement, and interference.

Moreover, neuromorphic computing mimics the neural systems of our brains to perform parallel computations; cloud computing moves processing to remote or virtual locations; and edge computing shifts processing from centralized facilities closer to end users.

All these developments in computing technology, which focus on tools and systems for processing, storing, and communicating data, have led to unprecedented advancements in fields including artificial intelligence (AI) and data analytics.

Ongoing research in the field has led to continued and rapid innovation in computing techniques, with scientists now going even deeper to achieve better, faster, and more efficient results.

Breakthrough in Laser Nanoscale Fabrication in Silicon

Researchers from Bilkent University, Turkey, recently achieved a significant breakthrough by developing a technique for fabricating nanostructures deep inside silicon wafers. 

The new method enables nanofabrication within silicon through spatial light modulation and laser pulses, creating advanced nanostructures that will benefit electronics and photonics.

The study focused on silicon, the foundation of electronics, photonics, and photovoltaics. As a semiconductor, Silicon's electrical conductivity lies between that of an insulator and a pure conductor. It is the second most abundant element in the Earth's crust, possessing both metallic and non-metallic properties. Additionally, Silicon's excellent electrical properties, including its relatively small energy gap, make it an important material in the semiconductor industry.

However, silicone has been limited to surface-level nanofabrication due to the difficulties posed by existing lithographic techniques. Current methods are either unable to penetrate the surface of the wafer without causing any changes or are restricted by the resolution of laser lithography. Additionally, existing techniques do not allow for high-precision modulation deep within the wafer. 

If devices could be directly fabricated inside the bulk of this metal without altering the wafer's top or bottom surface, it would set a new standard.

Of course, that means getting past all these challenges of a greater-than-1-micron fabrication resolution limit while simultaneously achieving multi-dimensional nanoscale control inside the wafer. Doing so, however, would be a magic advance, enabling 3D nanophotonics novel functionalities and leading to metasurfaces inside Si. 

The latest research went on to exploit spatially modulated laser beams and anisotropic feedback from preformed subsurface structures to achieve this. This allowed the team to establish controlled nanofabrication capability inside Si by manipulating matter at the nanoscale. 

To elaborate, the Bilkent team addressed the challenge of complex optical effects within the wafer and the inherent diffraction limit of the laser light by utilizing the unique laser pulse, which was created by modulating the spatial. The spatially modulated laser pulses correspond to a Bessel function. 

The optical scattering effects, which had been obstructing the precise deposition of energy, were then overcome by the special laser beam's non-diffracting nature. This non-diffracting nature is created with advanced holographic projection techniques, which allows for the precise localization of energy. This leads to high enough pressure and temperature values to modify the material at a small volume. 

According to Onur Tokel, Professor at the Department of Physics:

“Our approach is based on localizing the energy of the laser pulse within a semiconductor material to an extremely small volume, such that one can exploit emergent field enhancement effects analogous to those in plasmonics. This leads to sub-wavelength and multi-dimensional control directly inside the material.”

He added:

“We can now fabricate nanophotonic elements buried in silicon, such as nanogratings with high diffraction efficiency and even spectral control.”

This was followed by an emergent seeding effect, where nano-voids performed on the subsurface created a strong field enhancement in their close surroundings. Once established, the resulting field enhancement sustains itself, which means that the creation of earlier nanostructures helps fabricate the later nanostructures. 

Meanwhile, the use of laser polarization provided researchers with additional control over nanostructures' alignment and symmetry at the nanoscale, which allows the accurate development of varied nano-arrays.

“By leveraging the anisotropic feedback mechanism found in the laser-material interaction system, we achieved polarization-controlled nanolithography in silicon.”

– The study lead author, Dr. Asgari Sabet 

This new fabrication method has achieved feature sizes as small as 100 nm, which is a great improvement over the conventional regimes. 

This study could have considerable