Kelvin F. Poole

Rapid photothermal processing as a semiconductor manufacturing technology for the 21st century

The interactions of photons below about 800 nm provide thermal effects and quantum photo-effects. The performance of rapid thermal processing (RTP) techniques can be improved manifold by exploiting the use of quantum photo-effects in thermal processing. Photo excitations of species taking part in a chemical reaction or solid-state phenomena (e.g. annealing, solid-phase epitaxy etc.) lead to reduced activation energy. The quantum photo-effects dominated RTP is called rapid photothermal processing (RPP). At lower processing temperatures (compared to RTP), semiconductor devices with better performance, reliability and yields can be processed by RPP. Manufacturing of silicon integrated circuits (ICs) with dimension as low as 20 nm feature sizes is expected to dominate the 21st century. The ultra small feature size coupled with 12 in. (may be even 18 in.) diameter wafers will force the IC manufacturers to reduce the processing temperature to the point that only RPP can provide the desired performance, reliability and yields. This new era of low processing temperature of silicon IC processing will provide new capabilities in the processing of compound semiconductors related electronic and optical devices. The low-processing temperature aspect of RPP coupled with high throughput also opens new doors for large area devices such as solar cells and flat panel displays. The major challenge is the development of commercial equipment for manufacturing of ICs, solar cells and flat panel etc.

Annealing of silicon optical fibers

The recent realization of silicon core optical fibers has the potential for novel low insertion loss rack-to-rack optical interconnects and a number of other uses in sensing and biomedical applications. To the best of our knowledge, incoherent light source based rapid photothermal processing (RPP) was used for the first time to anneal glass-clad silicon core optical fibers. X-ray diffraction examination of the silicon core showed a considerable enhancement in the length and amount of single crystallinity post-annealing. Further, shifts in the Raman frequency of the silicon in the optical fiber core that were present in the as-drawn fibers were removed following the RPP treatment. Such results indicate that the RPP treatment increases the local crystallinity and therefore assists in the reduction of the local stresses in the core, leading to more homogenous fibers. The dark current-voltage characteristics of annealed silicon optical fiber diodes showed lower leakage current than the diodes based on as-draw...

Global green energy conversion revolution in 21 st century through solid state devices

Rising demands of energy in emerging economies coupled with the green house gas emissions related problems around the globe have provided a unique opportunity of exploiting the advantages offered by solid state devices (photovoltaic devices, thermoelectric devices, light emitting devices etc.) for green energy conversion. Similar to cell phones, power generation by photovoltaics (PV) can reach over two billion people worldwide who have no access to clean energy. Only silicon based PV devices meet the criterion of clean energy conversion (abundance of raw material and no environmental health and safety issues). Using larger size glass substrates and manufacturing techniques similar to the one used by liquid crystal display industry, the manufacturing cost of amorphous silicon thin films of

Role of rapid photothermal processing in process integration

1/wart can be achieved in the next one or two years. This will open a huge market for grid connected PV systems and related markets. With further R&D, this approach can provide a manufacturing cost goal of

Photovoltaics: Emerging role as a dominant electricity generation technology in the 21 st century

0.50/watt in the next 10 years. At this cost level, PV electricity generation is competitive with any other technology and PV generation can be a dominant electricity generation technology in the 21st century. In the areas of thermoelectric devices and light emitting diodes, more focused research is required to penetrate the market in a dominant way. Based on silicon CMOS technology, ambient energy harvesting will create its own niche market driven by the desire to produce communication, sensing and computing integrated systems with small form factor and no battery.

Importance of rapid photothermal processing in defect reduction and process integration

The smaller dimension devices and larger scales of integration are demanding constant reduction of the macroscopic and microscopic defects in the manufacturing of silicon integrated circuits. Increasing capital investment in manufacturing is forcing us toward processes and equipment that are effective not only in reduction of the cost of ownership but can also increase the effectiveness of equipment of current as well as future applications. Rapid thermal processing (RTP) based on incoherent light as the source of energy is playing an important role in the manufacturing of 300 nm and larger diameter wafers. The dominance of ultraviolet and vacuum ultraviolet photons in RTP results in rapid photothermal processing (RPP). The results presented in this paper show that the materials and devices processed by RPP are better than those processed by other thermal processes. This paper discusses the manufacturing science, operating principles of RPP and experimental results supporting its role in future process integration.

The effect of subtractive defects and grain size on VLSI interconnect early failure

Photovoltaics (PV) offer a unique opportunity to solve the 21st centurys electricity generation problem because solar energy is essentially unlimited and PV systems provide electricity without any undesirable impact on the environment. With current technology of silicon based PV systems, volume manufacturing, appropriate business model and without any subsidy, PV electricity can be generated today at the cost of less than

Characterization of AL–Y alloy thin films deposited by direct current magnetron sputtering

0.10/Wp. Silicon based PV systems will continue to dominate the PV market. Multi-junction PV systems based on Si and other abundant materials have the potential of manufacturing the next generation of ultra-low cost PV modules. For storing PV electricity there are many directions that have the potential of providing a low-cost solution. Overall, the future of PV electricity generation for rich and poor all over the world is bright.

The Effect of Interfacial Layers on High-Performance Gate Dielectrics Processed by RTP-ALD

Until recently, furnace processing had been one of the most popular methods for the manufacturing of the entire spectrum of semiconductor devices. As a result of shrinking device geometries and increasing wafer size, current trends are in the direction of single wafer processing. There is also a drive towards methods that address the long term requirements for reduced microscopic defects, lower processing temperatures, lower cost of ownership, reduced cycle times, smaller feature sizes and environmentally friendly processing of future generations of integrated circuits. The drive towards such an innovative process has stimulated higher heating and cooling rates along with the compatibility with single wafer technology make rapid thermal processing (RTP) as one of the most promising new thermal processing techniques. Recently introduced minifurnaces as well as RTP systems based on resistive heaters can also provide compatible heating and cooling rates. However, in terms of microscopic defeat reduction, thermal and residual stress reduction, as well as other processing needs, resistive heaters based RTP or minifurnaces do not offer any advantages over conventional furnace processing. Recently, we have shown that ultra violet (UV) and vacuum ultra violet (VUV) light sources when used in conjunction with tungsten halogen lamps based RTP can provide a process with lowest microscopic defects, lowest thermal and residual stress as well as built in green manufacturing feature. Rapid photothermal processing (RPP) also providing a platform for some of the fastest cycle times ever reported. This paper presents new results about the importance of RPP in achieved the desired performance of future semiconductor devices.

Improvements in resolution and dynamic range for FGMOS dosimetry

The effect of subtractive defects, similar in appearance to those caused by processing flaws such as photomask pinholes or stress voiding, on the reliability of VLSI interconnects is studied. Analysis of the metal microstructure and variations in the current density and temperature, show that small grained VLSI interconnects containing subtractive defects will have significant early failures. More importantly, when the grain size is large compared to the linewidth at the defect site, a good tolerance to defect-related early failures is expected. Experimental observations on 3 μm wide Al-based test stripes, containing semi-circular defects that remove up to 80% of the linewidth, support these arguments. The life tests were conducted at a nominal current density of 1.5 × 106Acm−2 to avoid the fusion regime, and at ambient temperatures of 80 °C, 125 °C and 200 °C, to study the influence of temperature. The influence of grain size was studied by using metallizations with mean grain sizes of 0.5 μm, 1 μm and 1.5 μm. Results confirm the analysis that, as long as the current density at the defect site is not high enough to cause the metal to fuse by Joule heating, the metal microstructure near a defect site is more important than the current density and temperature gradients.