We have visited Professor Michael Thwaites at RF sputtering company Plasma Quest in Hampshire in the UK. He is a professor at Southampton University and the majority owner of Plasma Quest. He founded Plasma Quest Ltd in 1998, assembling a small team of dedicated staff including 5 scientists and engineers (3 PhDs). The team now has an excellent and growing reputation for their plasma technology knowledge and expertise.
PQL has strong links with leading academic centres of excellence, with 1-2 post graduate students employed on site for much of the time. It is equipped with 3 HiTUS Sputter Deposition Systems; 1 High Density PECVD system and 1 E-beam coater, along with a basic analytical suit including an SEM and spectrophotometer. Its academic links additionally give it access to more specialised analytical equipment, usually on very fast turn around.
Its primary focus is on using its own technology for the deposition of thin film materials in a variety of applications, notably:
- Contract R&D - from 'proving' trials to full scale process development and production trials
- Full Remote Plasma System design and build / retrofit service
- HiTUS System commissioning, process consultancy and training
We learnt of many startling advances achieved in its various collaborative projects but unfortunately most of this work remains confidential. We shall reveal it in Printed Electronics Review when permission is forthcoming.
Basically, Plasma Quest is in the business of selling RF sputtering machines with unique geometry and physics and associated know how and IP. These remarkable machines provide stress-controlled, multilayer films on an unusually wide choice of substrates, and over increasingly large areas, because the process is carried out at ambient temperatures, whether reactive or not. Both crystalline and amorphous layers are deposited.
Its HiTUS technology has proved to be especially beneficial for:
- High rate reactive deposition for dielectric material deposition - near ideal RI and electrical breakdown
- High rate deposition of magnetic materials using thick targets (up to 15mm thick at present)
- Stable stoichiometric film deposition from compound, alloyed or mixed material targets
- Low temperature deposition for plastic or other 'delicate' substrates.
Flexible electronics
Flexible electronics is a primary focus but machines producing optical, magnetic and other films are also an interest. For example, work is proceeding on using ZnO based semiconductors in transparent transistors employing hafnium oxide dielectric for high permittivity. These have much better mobility and therefore higher frequency capability than organic transistors. This parallels similar work at Hewlett Packard/ Oregon State University and Toppan Printing/ Tokyo Institute of Technology and other groupings but they use printing rather than sputtering to make these devices. Exceptional adhesion is another unique with Plasma Quest equipment, flexible gold being one demonstration of this.
Plasma Quest, in partnership with the University of Southampton Civil Engineering Department and Romag won valuable DTI funding for a two year programme to develop flexible silicon solar cells in 2006 and work continues. The objective is to develop flexible solar cells using PQL's patented high density plasma sputtering technology for the deposition of semi conductor quality silicon. It will provide the solution to producing high rate, low cost solar cells, manufactured in an environmentally friendly way, without the use of toxic gases, according to the company.
The problems of toxic and global warming gases in current production of silicon solar cells are extremely severe as we revealed in Pollution challenges for photovoltaics.
For more attend Photovoltaics Beyond Conventional Silicon USA 2009 Dec 2-3, San Jose, USA.
