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SKKU Prof. Lee Young Hee creates new semiconductor base material surpassing silicon 2015.07.31
이승한 Views : 7534 Attach ( 0 ) 게시글 내용 This could replace your silicon computer chips - A new semiconductor material made from black phosphorus may be a candidate to replace silicon in future tech Silicon Valley in Northern California got its nickname from the multitude of computer chip manufacturers that sprung up in the surrounding area in the 1980’s. Despite its ubiquity as a chip building material, silicon may be facing some competition from a new version of an old substance. Researchers working at the Institute for Basic Science (IBS) Center for Integrated Nanostructure Physics in Suwon South Korea, led in part by Dr. Young Hee Lee, have created a high performance transistor using black phosphorus (BP) which has revealed some fascinating results. Transistors are made up of materials with semiconducting properties, which come in two varieties: n-type and p-type. While it is possible to have both types in different regions of one semiconductor crystal, the type cannot be changed. However, with the new BP crystal, researchers have discovered that it can be either a high performance n-type, ambipolar, or a p-type semiconductor depending only on thickness and the metal used in the contact leads. What does this mean? Silicon has to be doped (inserting another element into its crystal structure) in order for it to work in a semiconductor chip. The BP crystals can operate as both n-type and p-type or something in between, but without the doping. This means that instead of having a silicon-arsenic crystal sandwiched between silicon-boron crystals a transistor can have a single, lightweight, pure phosphorene logic chip. Why is this important? Technology manufacturers are in an arms race to make their devices lighter, smaller and more efficient. One example is tiny autonomous data recording and transmitting devices which will make up the Internet of Things (IoT). A major constraint from preventing IoT from taking off immediately is the inability to scale down the component size and the lack of a long-term power solution. 2D layered materials are interesting in this aspect, since both the electrical and mechanical properties are often enhanced compared to their bulk counterparts. The excellent switching characteristics and possibility of large electron and hole mobilities in BP is promising for CMOS (Complementary Metal Oxide Semiconductor) integration. These improvements can permit CMOS circuits to operate at lower voltages while also increasing performance, which translates to greatly reduced power consumption. Is it ready to compete with silicon? Unlike other industry standard semiconductor materials, there isn’t a good method for making pure BP on a large scale. Currently, thin layers can be made only from scraping bulk crystalline BP samples, as no other manufacturing method exists yet. Tackling the scaling problem is already underway, with chemical vapor deposition (CVD) and other thin film growth techniques being investigated in labs across the world. Is BP a good alternative to current semiconductor materials? It is a great material for semiconductor use. With aluminum as a contact, thicker BP flakes (13 nanometer) show ambipolar properties similar to graphene while thin 3 nm flakes are unipolar n-type with switching on/off ratios greater than 105. The thinner they can make the material, the better the switching performance. <Fig1. Atomic structure of black phosphorus and n/p-type transistor property of BP transistor>

SKKU Prof. Lee Young Hee creates new semiconductor base material surpassing silicon 2015.07.31

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This could replace your silicon computer chips

- A new semiconductor material made from black phosphorus may be a candidate to replace silicon in future tech

Silicon Valley in Northern California got its nickname from the multitude of computer chip manufacturers that sprung up in the surrounding area in the 1980’s. Despite its ubiquity as a chip building material, silicon may be facing some competition from a new version of an old substance.

Researchers working at the Institute for Basic Science (IBS) Center for Integrated Nanostructure Physics in Suwon South Korea, led in part by Dr. Young Hee Lee, have created a high performance transistor using black phosphorus (BP) which has revealed some fascinating results.

Transistors are made up of materials with semiconducting properties, which come in two varieties: n-type and p-type. While it is possible to have both types in different regions of one semiconductor crystal, the type cannot be changed. However, with the new BP crystal, researchers have discovered that it can be either a high performance n-type, ambipolar, or a p-type semiconductor depending only on thickness and the metal used in the contact leads.

What does this mean?

Silicon has to be doped (inserting another element into its crystal structure) in order for it to work in a semiconductor chip. The BP crystals can operate as both n-type and p-type or something in between, but without the doping. This means that instead of having a silicon-arsenic crystal sandwiched between silicon-boron crystals a transistor can have a single, lightweight, pure phosphorene logic chip.

Why is this important?

Technology manufacturers are in an arms race to make their devices lighter, smaller and more efficient. One example is tiny autonomous data recording and transmitting devices which will make up the Internet of Things (IoT). A major constraint from preventing IoT from taking off immediately is the inability to scale down the component size and the lack of a long-term power solution. 2D layered materials are interesting in this aspect, since both the electrical and mechanical properties are often enhanced compared to their bulk counterparts. The excellent switching characteristics and possibility of large electron and hole mobilities in BP is promising for CMOS (Complementary Metal Oxide Semiconductor) integration. These improvements can permit CMOS circuits to operate at lower voltages while also increasing performance, which translates to greatly reduced power consumption.

Is it ready to compete with silicon?

Unlike other industry standard semiconductor materials, there isn’t a good method for making pure BP on a large scale. Currently, thin layers can be made only from scraping bulk crystalline BP samples, as no other manufacturing method exists yet. Tackling the scaling problem is already underway, with chemical vapor deposition (CVD) and other thin film growth techniques being investigated in labs across the world.

Is BP a good alternative to current semiconductor materials?

It is a great material for semiconductor use. With aluminum as a contact, thicker BP flakes (13 nanometer) show ambipolar properties similar to graphene while thin 3 nm flakes are unipolar n-type with switching on/off ratios greater than 105. The thinner they can make the material, the better the switching performance.