+44 (0)24 7671 8970
More publications     •     Advertise with us     •     Contact us
*/
News Article

Coventry uni seeks partners

Coventry University Enterprises is seeking industrial partners and licencees for silicon technologies developed at the UK university.
Coventry University Enterprises is seeking industrial partners and licencees for silicon technologies developed at the UK university.

One development in nanoscale physics concerns electron beam resist materials. Two types have been produced based on methanofullerene and polysubstituted triphenylene compounds. A method for forming a finely patterned resist layer on a substrate surface for use in devices such as electronic or semiconductor nanocircuits has achieved fine patterning with a high aspect ratio. The university is seeking licensees to exploit this technology.

A second, patented, technology covers production of microscopic silicon pillars and cones and ordered arrays of microscopic pillars. Hoped for applications include hot emission lithography, gas sensors, flat panel displays and optoelectronics. The university is now seeking industrial partners interested in developing this technology for incorporation into their production processes through licences or joint ventures.

Nanometre resist The new electron-beam resist aims at overcoming the patterning limitations of current materials that are reaching the molecular dimensions of the resinous ingredient. For example, novolac resin-based electron beam resist materials cannot pattern finer than several tens of nanometers because at best the molecules mostly have a molecular size of at least a few nanometers. Methacrylic resin-based positive tone electron beam resist materials produce a pattern resolution of fineness of about 10nm but the resistance of the layer against dry etch is relatively poor.

Coventry's polysubstituted triphenylene has a molecular diameter of 1-3nm, thus meeting the requirements for high patterning resolution and high etch durability. It has sufficient solubility in various organic solvents that via the spin coating method, films of thickness from less than 10nm can easily be produced. In tests against commercially available novolac resin-based resist composition, the polysubstituted triphenylene produced a relative etching resistance of 3.2 compared with the commercial material's value of 3.

The university researchers have also discovered a methanofulerene compound, with one or more adduct groups in the compound with a molecular size of around 1nm or smaller. This material is soluble in an organic solvent but can be made insoluble by irradiation with electron beams. The compound is easily prepared and performs well against current resists such as the novolac-based materials.

Pillars and cones The silicon pillars and cones are produced by depositing an etch-resistant material onto the wafer surface. One technique is to use size selected silver clusters as the etchable material sputtered onto the surface. In another technique, a self-assembled ordered array of clusters may be used to produce an ordered array of projections. Plasma etching is carried out by using CF4 and SF6 gases at 8mTorr pressure. By using different rf power sequences, the shape of the silicon material remaining after etch can be controlled to give pillars or cones with varying angles between the side walls.

Cones have been produced with tip radius of about 10nm, average base width of 50nm and average height of 150nm. These cones can be coated with an oxide layer and then a metal to produce an electrode array of cold cathode electron sources for applications in flat panel displays and gas sensors. They also have applications in multiple tip scanning probe microscopy and the manufacture of field electron emitters for use in hot emission lithography.

Pillars have been produced with a diameter about 17nm and height greater than 100nm by use of silver clusters containing greater than 300 atoms. Under specific conditions pillars can be fabricated with mean diameter 10nm with self-formed etching masks.

Ordered arrays of pillars have been produced by using an aqueous solution containing polystyrene balls of 500nm diameter which is then dropped onto a hydrophilic oxygen terminated silicon surface thus promoting an even spread of the solution over the surface. The solution is then dried to produce a monolayer of balls. Another method of producing a more perfect monolayer involves the use of a surfactant and spin coating the balls onto the surface. A metal is then deposited on the surface (i.e. size selected silver clusters), which reaches the silicon surface between the polystyrene balls.

These are then dissolved in chloroform in an ultrasonic bath to leave metal peaks in a hexagonal pattern on the silicon surface and again etching is carried out. The arrays of pillars have potential use in optoelectronics where they are expected to exhibit photoluminescence and/or electroluminescence.

http://www.mirc.org.uk

×
Search the news archive

To close this popup you can press escape or click the close icon.
Logo
×
Logo
×
Register - Step 1

You may choose to subscribe to the Silicon Semiconductor Magazine, the Silicon Semiconductor Newsletter, or both. You may also request additional information if required, before submitting your application.


Please subscribe me to:

 

You chose the industry type of "Other"

Please enter the industry that you work in:
Please enter the industry that you work in: