Featured Research

from universities, journals, and other organizations

High, not flat: nanowires for a new chip architecture

Date:
February 10, 2010
Source:
Forschungszentrum Dresden Rossendorf
Summary:
Silicon is the most prevalent material in electronics, whether for mobile phones, solar cells or computers. Nanometer-sized wires made of silicon have a large potential for a completely new chip architecture. But this requires a detailed investigation and understanding of their electronic properties which is technologically challenging due to the ultra-small size of the nanowires. Researchers were able to describe the electrical resistance and current flow inside individual silicon nanowires.

Scheme of a silicon wafer with novel vertical transistors made out of silicon nanowires (without the upper p-contact).
Credit: Image courtesy of Forschungszentrum Dresden Rossendorf

A myriad of silicon transistors are responsible to pass on the information on a microchip with today's technology. The transistors are arranged in a planar array, i.e. lying flat next to each other, and have shrunk down already to a size of only about 50 nanometers (1 nanometer = 1 millionth part of 1 millimeter). Further miniaturization of transistors with a planar structure will soon come to an end due to fundamental physical limits. Still, even smaller transistors are desirable in order to continuously improve their functions while reducing the cost of the electronics.

Currently, researchers are working hard to find new approaches to overcome the physical limits on downscaling and integration of microchips. One such concept is to fabricate a completely new transistor architecture in three-dimensions. In this concept, instead of arranging them flat on the substrate the silicon transistors are turned by 90 degrees so that they stick out of the chip substrate like tiny columns. In this way, numerous vertical transistors could be built on the area normally occupied by only one planar transistor. This would finally be the step from micro to nanoelectronics.

The fabrication of vertical silicon nanowire arrays has already been reported. Yet there needs to be a more thorough research into the electrical properties of silicon nanowires in order to be able to build reliable transistors for a new generation of microchips. Unlike conventional transistors, the current flow in these column-like transistors will be vertical, and they will be smaller and more energy-saving than today. Last but not least, there are high hopes to fabricate extremely efficient solar cells using silicon nanowires.

The Max Planck researchers in Halle produce monocrystalline silicon nanowires which are particularly suitable as components for microchips. At the FZD's ion beam center, foreign atoms known as 'dopants' are implanted into the nanowires. The dopants occupy lattice sites of the host semiconductor increasing the electrical conductivity and the current flow through the semiconductor. Selective implantation of different dopants can change the polarity of the charge carriers in a transistor leading to the switching of the current flow. The planar silicon technology is well developed; however, this is not true for silicon nanostructures. "First, we analyzed wires with a diameter of 100 nanometers and 300 nanometers in length. But what we aim at are wires with a diameter of a few atoms only, as well as wires where individual atoms are strung together. We intend to closely characterize their behavior in materials and want to find out how their electrical properties can be tailored for application in nanoelectronics, e.g. for new field-effect transistors," say FZD physicists Dr. Reinhard Koegler and Dr. Xin Ou.

The nanowires were investigated in Rossendorf using a technique (Scanning Spreading Resistance Microscopy, SSRM) that usually measures the position- dependent electrical resistivity in a specially-prepared two-dimensional cross-section of the nanowire. The resistivity is related to the atomic concentration of the dopants. In the current work, the researchers have found that the dopants in a silicon nanowire, namely boron and phorphorus, do not stay where they are expected, but drift to the surface of the nanowire where they become partially inactive and can no longer contribute to the electrical conductivity. Up until now scientists were lacking an appropriate technique to visualize and quantify the consequences of an unequal distribution of dopants at the nanoscale. Chip designers have to pay attention to the newly found results if nanowires are to be applied for vertical transistors in the future.


Story Source:

The above story is based on materials provided by Forschungszentrum Dresden Rossendorf. Note: Materials may be edited for content and length.


Journal Reference:

  1. Ou et al. Carrier Profiling of Individual Si Nanowires by Scanning Spreading Resistance Microscopy. Nano Letters, 2010; 10 (1): 171 DOI: 10.1021/nl903228s

Cite This Page:

Forschungszentrum Dresden Rossendorf. "High, not flat: nanowires for a new chip architecture." ScienceDaily. ScienceDaily, 10 February 2010. <www.sciencedaily.com/releases/2010/02/100202103625.htm>.
Forschungszentrum Dresden Rossendorf. (2010, February 10). High, not flat: nanowires for a new chip architecture. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2010/02/100202103625.htm
Forschungszentrum Dresden Rossendorf. "High, not flat: nanowires for a new chip architecture." ScienceDaily. www.sciencedaily.com/releases/2010/02/100202103625.htm (accessed July 22, 2014).

Share This




More Matter & Energy News

Tuesday, July 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Government Approves East Coast Oil Exploration

Government Approves East Coast Oil Exploration

AP (July 18, 2014) The Obama administration approved the use of sonic cannons to discover deposits under the ocean floor by shooting sound waves 100 times louder than a jet engine through waters shared by endangered whales and turtles. (July 18) Video provided by AP
Powered by NewsLook.com
Sunken German U-Boat Clearly Visible For First Time

Sunken German U-Boat Clearly Visible For First Time

Newsy (July 18, 2014) The wreckage of the German submarine U-166 has become clearly visible for the first time since it was discovered in 2001. Video provided by Newsy
Powered by NewsLook.com
Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Reuters - US Online Video (July 17, 2014) President Barak Obama stopped by at a lunch counter in Delaware before making remarks about boosting the nation's infrastructure. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

TheStreet (July 16, 2014) Oil Futures are bouncing back after tumbling below $100 a barrel for the first time since May yesterday. Jeff Grossman is the president of BRG Brokerage and trades at the NYMEX. Grossman tells TheStreet the Middle East is always a concern for oil traders. Oil prices were pushed down in recent weeks on Libya increasing its production. Supply disruptions in Iraq fading also contributed to prices falling. News from China's economic front showing a growth for the second quarter also calmed fears on its slowdown. Jeff Grossman talks to TheStreet's Susannah Lee on this and more on the Energy Department's Energy Information Administration (EIA) report. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins