Despite Recent Technological Limits, Researchers Find a New Method to Make Computer Chips Smaller and Faster

Up to recent times, computer processors, or computer chips, have continuously gotten smaller, faster, and more efficient. Researchers are seeing a blockade these days because it is becoming too expensive and too difficult to make computer chips any smaller and faster due to physical constraints. However, a team of engineers from the University of Wisconsin-Madison and the University of Chicago found a way to coat a germanium wafer, which is the base of a computer chip, with a layer of pure graphene that is only one-atom thick. This incredibly thin sheet of carbon, which is shown in the picture to the right, is also compatible for mass production, allowing for a wide range of smaller and faster features.

People Doubt Moore's Law, Which States That the Number of Transistors in Computer Chips Doubles Every Two Years


Moore's Law is an observation that Gordon Moore, co-founder of Intel, made in 1965. He stated that the number of transistors per square inch on a computer chip had doubled every two years ever since the first integrated circuit was invented in 1958. The figure to the right illustrates this trend from 1971 up to 2011.

Transistors are tiny components in computer chips that process electrical signals, and when they are packed more densely together, the efficiency and processing speed of the computer chip increases. With the exponential growth of technology, manufacturers were continually able to find ways to make computer chips smaller in size but able to contain more memory and perform faster at the same time. However, the size of transistors are currently approaching the atomic scale, and there are physical limits to how they can fit in the circuitry.

Although there were constant advancements in microelectronics up to recent times, researchers are now struggling to make additional innovations due to dimensional boundaries. Indeed, it is becoming too expensive and too difficult to make computer chips any smaller and faster. Nowadays, many people are seeing an end to Moore's Law and are doubting its continual trend. This is illustrated by the figure to the right, which highlights the current as well as the future predictions of the transistor density count in computer chips.

Researchers Use One-Atom Thick Graphene to find a Technological Breakthrough

Despite the current limitations in electronic system design, a team of engineers from the University of Wisconsin-Madison and the University of Chicago devised a simpler, reproducible, and less expensive manufacturing approach. They found a way to coat a germanium wafer with a layer of pure graphene, which is a sheet of carbon that is only one atom thick. Germanium (Ge) has an atomic number of 32 from the periodic table of elements, and it is a lustrous, hard, and grayish-white metal that has similar appearance and properties as silicon, which is a material that is also commonly used as the base for computer chips. Their ability to manufacture the thin film of graphene onto this germanium wafer will decrease the size of computer chips, boost the functionality for semiconductor electronics, as well as substantially increase the capacity for data storage.

The team of engineers published details of the discovery in an edition of the journal, "Scientific Reports." The manufacturing method involves the use of directed self-assembly, which is a large-scale nano-patterning technique that increases the density of the circuit patterns. Manufacturers are developing this method to achieve the incredibly tiny size required for circuitry in future semiconductors of electronics. The researchers' new method is much faster than the traditional one and reduces the number of steps in the process to just two: lithography and plasma etching. These two processes are used in order to pattern graphene strips onto the germanium wafer that are just one atom thick. The uniform pattern that results from the manufacturing process is shown in the pictures to the right, which were taking by using a scanning electron microscope.

The Manufacturing Method: Lithography and Plasma Etching

For directed self-assembly, the researchers used chemical techniques to define a pre-pattern onto the germanium wafer. Defining a pre-pattern enables the block copolymer, which is the graphene in this case, to self-assemble onto the pre-pattern in order to form intricate and perfectly ordered features for circuitry. According the, "When heated, the block copolymer self-assembled completely in just 10 minutes compared to 30 minutes using conventional chemical patterns and with fewer defects. The researchers attribute this rapid assembly to the smooth, rigid, crystalline surfaces of germanium and graphene." The illustration of this process is shown in the figure to the right.

Researchers used electron beam lithography in order to first create a larger template of extremely thinly spaced patterns that guide the orientation of the one-atom thick graphene strips. Electron beam lithography is the practice of scanning a focused beam of electrons to draw custom shapes on a surface that is covered with an electron-sensitive film. The primary advantage of electron beam lithography is that it can draw custom patterns with less than a 10-nanometer resolution, which is necessary for this scale of manufacturing.

Then, plasma etching was used to finalize the pattern onto the computer chip. Plasma is one of the four fundamental states of matter, which includes solid, liquid, and gas. Plasma is created by either heating or applying a strong magnetic field to gas, allowing the gas to have a glowing attribute. Plasma etching is the use of a high-speed stream of plasma in order to finish a print pattern onto a surface. In this manufacturing method, plasma etching was used to embed the graphene patterns onto the germanium wafer.

"Using this one-atom thick graphene template has never been done before. It's a new template to guide the self-assembly of the polymers," says Ma, an electrical engineer at UW-Madison. "This is mass-production-compatible. We opened the door to even smaller features." Indeed, their work could possibly mean a breakthrough to current technological blockades in order to validate Moore's Law, once again. However, there will still be people with doubts such as the student in the following video. He is currently a fire protection engineering major at the University of Maryland.

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