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 October 23, 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 October 23, 2014).

Share This



More Matter & Energy News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Reuters - Innovations Video Online (Oct. 22, 2014) — Inspired by the way a chameleon changes its colour to disguise itself; scientists in Poland want to replace traditional camouflage paint with thousands of electrochromic plates that will continuously change colour to blend with its surroundings. The first PL-01 concept tank prototype will be tested within a few years, with scientists predicting that a similar technology could even be woven into the fabric of a soldiers' clothing making them virtually invisible to the naked eye. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Jet Sales Lift Boeing Profit 18 Pct.

Jet Sales Lift Boeing Profit 18 Pct.

Reuters - Business Video Online (Oct. 22, 2014) — Strong jet demand has pushed Boeing to raise its profit forecast for the third time, but analysts were disappointed by its small cash flow. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) — As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) Video provided by AP
Powered by NewsLook.com
What Is Magic Leap, And Why Is It Worth $500M?

What Is Magic Leap, And Why Is It Worth $500M?

Newsy (Oct. 22, 2014) — Magic Leap isn't publicizing much more than a description of its product, but it’s been enough for Google and others to invest more than $500M. Video provided by Newsy
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:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

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