Stories with Tag integrated circuit

• A 32-bit processor made with an atomically thin semiconductor

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  Posted: 2025-04-08 13:08:49

  Verbose tl;dr

  Researchers have built a 32-bit RISC-V processor using a monolayer of molybdenum disulfide (MoS₂), a two-dimensional semiconductor. This achievement demonstrates the potential of 2D materials for creating extremely thin and energy-efficient transistors, pushing the boundaries of Moore's Law. While slower and larger than state-of-the-art silicon chips, this prototype represents a significant step towards practical applications of 2D semiconductors in computing. The processor, dubbed RV16XNano, successfully executed instructions and represents a promising foundation for future development of more complex and powerful 2D-material-based circuits.

  In a significant advancement for the field of semiconductor technology, researchers have successfully constructed a functional 32-bit microprocessor utilizing an atomically thin, two-dimensional semiconductor material – specifically, molybdenum disulfide (MoS₂). This achievement, detailed in a recent publication in Nature, marks a pivotal step towards realizing the potential of 2D materials in high-performance computing and overcomes several long-standing challenges associated with their use in complex digital circuits.

  Traditionally, silicon has been the dominant material in semiconductor manufacturing. However, as silicon-based transistors approach their physical limitations in terms of miniaturization, researchers have been actively exploring alternative materials that can sustain Moore's Law and enable further advancements in computing power and efficiency. Two-dimensional materials, with their unique electrical and mechanical properties, have emerged as promising candidates. Among them, MoS₂, a transition metal dichalcogenide, has garnered considerable attention due to its inherent thinness and potential for low-power operation.

  The fabricated processor, based on the open-source RISC-V instruction set architecture, comprises 115 transistors formed from monolayer MoS₂. This relatively simple architecture allows for a thorough demonstration of the material's capabilities in performing logical operations and executing programmed instructions. The researchers meticulously optimized the transistor design and fabrication process to overcome inherent challenges associated with 2D materials, including contact resistance and mobility variations. They employed a back-gated configuration and utilized chemical vapor deposition to achieve high-quality MoS₂ films. Furthermore, they implemented a novel interconnect scheme to efficiently connect the individual transistors and form the functional circuits of the processor.

  The successful operation of this MoS₂-based processor demonstrates the feasibility of building complex digital circuits using atomically thin semiconductors. While the current prototype exhibits a relatively low clock speed and limited complexity compared to state-of-the-art silicon processors, it represents a crucial proof-of-concept. This achievement paves the way for future research exploring more complex architectures and higher performance levels using 2D materials. The potential benefits include ultra-thin and flexible electronics, significantly reduced power consumption, and novel functionalities enabled by the unique properties of these materials. This breakthrough could ultimately revolutionize computing and contribute to the development of next-generation electronic devices. The research team envisions that future iterations of this technology could lead to even more powerful and efficient processors based on 2D materials, potentially exceeding the limitations of current silicon-based technology.

  • 32-bit processor
  • RISC-V
  • 2D semiconductor
  • atomically thin
  • Transistor
  • integrated circuit
  • Computer Architecture
  • Electronics
  • nanotechnology
  • Material Science
  • semiconductor technology
  • Hardware
  • CPU

  Summary of Comments ( 39 )
  https://news.ycombinator.com/item?id=43621378

  Verbose tl;dr

  Hacker News users discuss the implications of a RISC-V processor built with a 2D semiconductor. Several express excitement about the potential for flexible electronics and extremely low power consumption, envisioning applications in wearables and IoT devices. Some question the practicality due to the current limitations in clock speed and memory integration, while others point out the significant achievement of creating a functional processor with this technology at all. A few commenters delve into the specifics of the fabrication process and the challenges of scaling this technology for commercial production. Concerns about the fragility of the material and the potential difficulty in handling and packaging are also raised. Overall, the sentiment leans towards cautious optimism about the long-term possibilities of 2D semiconductors in computing.

  The Hacker News post "A 32-bit processor made with an atomically thin semiconductor" discussing an Ars Technica article about a RISC-V processor built using a 2D semiconductor, generated a moderate number of comments, many of which delve into the technical details and potential implications of the research.

  Several commenters focused on the performance aspects. One noted the extremely low clock speed (1 kHz) and questioned the practical applications given this limitation. Another commenter built on this, explaining that the low clock speed is likely due to the high resistance of the thin semiconductor material. They further elaborated that while the transistor density could theoretically be much higher, the interconnect resistance would become a bottleneck.

  The discussion also touched upon the challenges of manufacturing and scaling this technology. A commenter pointed out that creating larger, more complex chips using this 2D material would be difficult due to defects. They questioned whether it would be possible to scale this to create a commercially viable product. Another commenter highlighted the specific challenges in achieving uniformity and consistency in a large-scale manufacturing process for atomically thin materials.

  The potential advantages of 2D semiconductors were also discussed. One commenter mentioned the possibility of flexible electronics, suggesting that this technology could pave the way for devices that are bendable or even foldable. Another commenter mentioned potential applications in areas where power consumption is extremely important since reducing the thickness to the atomic level can impact a device's energy requirements.

  Some comments delved into the specifics of the RISC-V architecture. One commenter pointed out that while the processor is a 32-bit RISC-V design, it lacks features commonly found in modern processors, making it more of a proof-of-concept rather than a practical processor.

  Finally, a few commenters expressed skepticism, suggesting that this research, while interesting, is a long way from commercial viability. They emphasized that the current limitations in performance and manufacturing make it unlikely to replace existing silicon technology in the near future.

  In summary, the comments section explored the technical complexities, potential benefits, and significant challenges associated with using 2D semiconductors for processor design. While excitement was expressed for the potential of this technology, many commenters remained realistic about the long road ahead for commercialization.

• The bucket brigade device: An analog shift register

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  Posted: 2024-11-15 13:27:08

  Verbose tl;dr

  The Bucket Brigade Device (BBD) is an analog shift register implemented using a chain of capacitors and transistors. It stores analog signals as charge packets on these capacitors, sequentially transferring them along the chain with the help of a clock signal. This creates a time delay proportional to the number of stages in the brigade. BBDs were historically used for audio effects like delay, chorus, and reverberation because of their simplicity and relatively low cost. However, they suffer from signal degradation due to charge leakage and require careful biasing and clocking for optimal performance. Despite being largely superseded by digital technologies, BBDs offer a fascinating example of analog signal processing.

  The blog post "The bucket brigade device: An analog shift register" explores the fascinating functionality and historical significance of the bucket brigade device (BBD), an analog circuit capable of delaying analog signals. The author meticulously explains how this ingenious device operates by analogy to a line of firefighters passing buckets of water along a chain. Just as each firefighter receives a bucket from one neighbor and passes it to another, the BBD transfers packets of charge between adjacent capacitors. This transfer, controlled by a clock signal, effectively moves the analog signal down the chain of capacitors, creating a delay proportional to the number of stages and the clock frequency.

  The post delves into the underlying physics, describing how MOS transistors, acting as switches, facilitate the transfer of charge packets. It emphasizes the importance of the clock signal in coordinating this transfer and preventing the signal from degrading. The bidirectional nature of the charge transfer, allowing for both forward and reverse movement of the signal, is also highlighted. The author further elaborates on the advantages of using MOS capacitors for charge storage, emphasizing their small size and compatibility with integrated circuit technology.

  The post then explores the practical applications of BBDs, particularly their historical role in early electronic music synthesizers and other audio effects. By varying the clock frequency, the delay time can be modulated, creating effects like vibrato, chorus, and phasing. This dynamic control over the delay was crucial for achieving specific musical nuances and textures in these early electronic instruments. The author illustrates this point with examples and explanations of how these effects are achieved.

  Finally, the post touches upon the limitations of BBDs, including noise introduced during the charge transfer process and the eventual decay of the signal due to leakage currents. These imperfections, while inherent in the analog nature of the device, contribute to the characteristic "warmth" often associated with analog audio effects. Despite these limitations and their eventual replacement by digital technologies, the BBD remains a testament to ingenious analog circuit design and its impact on the development of electronic music. The author's detailed explanation and accompanying diagrams provide a comprehensive understanding of the BBD's operation and significance.

  • bucket brigade device
  • analog shift register
  • charge transfer device
  • CCD
  • analog delay line
  • analog signal processing
  • Electronics
  • integrated circuit
  • semiconductor device
  • MNOS
  • MOSFET
  • analog circuits
  • shift register
  • BBD
  • analog delay
  • Signal Processing
  • metal–nitride–oxide–semiconductor
  • MNOS transistor
  • metal-nitride-oxide-semiconductor

  Summary of Comments ( 29 )
  https://news.ycombinator.com/item?id=42146718

  Verbose tl;dr

  HN users generally found the bucket brigade device fascinating. Several commenters discussed practical applications like its use in early audio delay lines and the challenges of clocking it consistently. Others appreciated the clear explanation and visualization of the device's operation, highlighting its simplicity and elegance. Some compared it to charge-coupled devices (CCDs) and discussed their similarities and differences in functionality and implementation. The practicality of using actual buckets filled with water was also debated, with some suggesting the analogy, while visually appealing, might not accurately represent the underlying physics of the electronic device. A few users linked to relevant Wikipedia pages and other resources for further exploration.

  The Hacker News post "The bucket brigade device: An analog shift register" has generated several comments discussing various aspects of the technology.

  Several commenters focused on the practicality and applications of bucket brigade devices (BBDs). One commenter questioned their utility, asking why one would use a BBD instead of just storing samples digitally. This prompted a discussion about the historical context of BBDs, with others pointing out that they predate readily available digital solutions and were used in applications like early synthesizers and guitar effects pedals due to their simplicity and relatively low cost at the time. Another commenter mentioned the use of BBDs in toys and musical greeting cards. This highlighted the BBD's suitability for low-fidelity audio where digital solutions might have been overkill. Someone else mentioned the distinct "analog" sound of BBDs, specifically their characteristic warble and degradation, which became desirable in some musical applications, contributing to their continued niche usage.

  The technical aspects of BBD operation also drew attention. One commenter clarified the functionality, explaining that the charge isn't actually moved across the entire chain of capacitors, but rather small amounts of charge are passed between adjacent capacitors, analogous to a bucket brigade. This clarified the name and underlying principle for other readers. Another comment delved deeper into the physical implementation, describing the use of MOS capacitors and the impact of clock frequency on the delay time.

  One commenter reminisced about experimenting with BBDs and other analog components in their youth. This added a personal touch to the discussion and underscored the historical significance of these devices for hobbyists and early electronics enthusiasts.

  A recurring theme in the comments was the contrast between BBDs and digital delay lines. Commenters explored the trade-offs between the simplicity and unique sound of BBDs versus the fidelity and flexibility of digital approaches. The limitations of BBDs, such as their fixed maximum delay time and susceptibility to noise, were also mentioned. One commenter even discussed the specific challenges of clocking BBDs and the impact of clock imperfections on the output signal.

  Finally, a couple of comments highlighted related technologies, including the use of CCDs (charge-coupled devices) for similar signal processing applications, and drawing parallels with the operation of peristaltic pumps. These broadened the context of the discussion and provided additional avenues for exploration.