The first author of this study was Zhang Yi, a postgraduate of the Zhejiang University's School of Information and Electronic Engineering, and the author of the communication was Zhao Yi, who is a candidate for the Thousand Youth Program.
Memory, as the name suggests, is a device that stores information. Content-addressable memory is a special one. In early chips, when entering a network address, a large number of searches were needed to find the corresponding interface before data access was possible. In the process of matching, the efficiency is very low; content-addressable memory is like having a large number of sought-after 'frog mothers' stored in it to shout out names to achieve fast search and match.
How to make this process more efficient and time-consuming is an important issue that scientists focus on.
Develop 'Memory Diodes'
To make the search time short, first of all remember to remember more, remember clever.
The common memristor is a typical non-volatile memory, but the problem is that ordinary memristor data input and output is not divided into ports, thus making the circuit easy to form disturbances and interference. How can the current path be unidirectional? People seek inspiration from the features of the biological synapses in one-way conduction to prevent information interference; hopefully based on the commonly used diodes that have similar unidirectional transfer characteristics of electronic devices to achieve the corresponding function.
So how can we combine non-unidirectional memristors with diodes capable of single items? The task group has found a lot of experiments to find this semiconductor material. In previous years, Zhao Yi's research group has been confronted with logic devices. The application has been in-depth research and exploration. This time, they used the unique surface properties of germanium to grow memristor materials on the surface of germanium and form a new device. Zhao Yi's group called it a 'memory diode'.
Zhao Yi said: 'The new device developed by our research group will use a single device to realize its functions that would otherwise require a circuit.' This new device significantly reduces the chip area and miniaturizes mobile phones and other devices. In electronic devices, such a reduction can 'vacate' a lot of space for the realization of other functions. Zhao Yi's research group can form a memory unit with only two memory diodes, and the use area is reduced by a few tenths.
To achieve more or less, how to achieve fast?
The common ip address consists of multiple fields. The traditional 'two-state comparison' carries out one-to-one search and comparison from the 0, 1 two dimensions. This two-state comparison shows no disadvantage in small-scale data. However, when the data reaches a certain order of magnitude, it shows the general inefficiency of 'manual'.
The tri-state comparison shows its advantages. The contrast coverage is enhanced by the three dimensions of 0, 1, and X. 'x is equivalent to the 'packing' of the same field. Through this blurring process, the comparison field can be shortened. The three states are realized by the combination of the two states of the “on” and “off” of the memory diodes, thereby accelerating the data circulation and contributing to the acceleration of the overall Internet speed. Zhao Yi introduced that this acceleration may be for example within a region. Only one or two mobile phones can't appear so obvious, but when the population is dense, its advantages can be revealed.
In the social networking of the Internet of Things 'tagging' There are two main types of chip storage technology. The first type is volatile storage, such as computer memory, but the data will disappear immediately after a power failure; the second type is non-volatile storage, such as U disk, after writing data without additional energy can also save 10 years.
Zhejiang University developed a memory diode array consisting of three-state addressable memory, because the original memristor is non-volatile, so the entire addressable memory has almost no energy consumption in the sleep state. Because of the simpler construction method, Its production cost is also greatly reduced compared to the original.
Scientists applied these two major advantages and conceived new applications for the new devices they developed in the future.
For example, this memory technology can also improve computer scientists' ability to handle 'big data' by 'tagging' data. This makes searching easier. ' Existing IP addresses are actually a type of tag. You can choose to pass some data to somewhere via ip. 'Zhao Yi introduced, 'If you just quote the current technology, you have to pass every data tag and the cost threshold, and the memory diode array developed The tristate addressable memory completely eliminates cost considerations.
The research paper was accepted by the 2018 Symposia on VLSI Technology and Circuits. This conference is a top international conference in the field of integrated circuits. It enjoys a high academic status in the academic and industrial circles of the international integrated circuit industry. And extensive influence. This is the first time Zhejiang University published a paper on Symposia on VLSI Technology and Circuits.
The study was supported by the national key R&D program and the National Natural Science Foundation of China.