Peter H. Rose

Development of the Calorimeter Heat Transfer Gauge for Use in Shock Tubes

A heat transfer gauge suitable for measuring extremely high heat transfer rates under the quasi‐transient conditions occurring in shock tubes has been developed. The instrument is based on a calorimetric principle and is made possible by the short steady state times inherent in shock tubes. The technique developed extends, verifies, and supplements the shock tube heat transfer measurements made by thin film resistance thermometers.The operating principles and experimental experiences with calorimeter heat transfer gauges are reported in some detail.Much heat transfer data obtained with calorimeter gauges has been collected and published. Experimental measurements of laminar and turbulent heat transfer rates at velocities up to satellite speeds, approximately 26 000 ft/sec, have been reported. Heat transfer rates as high as 40 kw/cm2 have been encountered in these experiments.

A history of commercial implantation

Abstract History has many voices and in this one the speaker will endeavor to describe the circumstances that molded the equipment manufacturing companies in which he has been involved since 1956. The talk will concentrate on those activities in which the author was personally concerned. The ion implanter as we now know it has evolved from an intricate background of technologies in nuclear, atomic, and electron physics. In a very short period the equipment available for wafer processing has changed from a laboratory instrument to a sophisticated piece of production equipment. In the early days it was difficult to satisfy the most elementary customer requirements such as dose uniformity and accuracy let alone reliability. In a span of ten years the improvements have been remarkable and yet at the same time the criteria by which equipment is judged has tightened and the same shortcomings still have a priority. However to the list of implanter parameters other factors have emerged such as automation, charge neutralization, particulates and temperature control of the targets, so that the design of new equipment becomes increasingly complicated.

Concepts and designs of ion implantation equipment for semiconductor processing

Manufacturing ion implantation equipment for doping semiconductors has grown into a two billion dollar business. The accelerators developed for nuclear physics research and isotope separation provided the technology from which ion implanters have been developed but the unique requirements of the semiconductor industry defined the evolution of the architecture of these small accelerators. Key elements will be described including ion generation and beam transport systems as well as the techniques used to achieve uniform doping over large wafers. The wafers are processed one at a time or in batches and are moved in and out of the vacuum by automated handling systems. The productivity of an implanter is of economic importance and there is continuing need to increase the usable beam current especially at low energies.

The evolution of ion sources for implanters (invited)

Ion sources have improved in performance and reliability to such a degree that they can be operated completely under computer control. The improvements in design and fabrication that have made this possible are the result of many years of effort, and yet there are still serious shortcomings. For example, there is still a need for a several times improvement in lifetime and it is questionable whether this can be achieved by further evolution of existing designs. Perhaps the answer to better performance may be found by replacing the electron emitting filament used in almost all sources today by a source using rf or microwaves for plasma excitation.

A high-energy, high-current ion implantation system

Abstract High current (Pre-DepTM) ion implanters, operating at 80 keV, have met a need in the semiconductor industry. For certain processes, higher energies are required, either to penetrate a surface layer or to place the dopant ion at a greater depth. The Eaton/Nova Model NV10-160 Pre-DepTM Ion Implanter has been developed to meet those special needs. Beam currents as high as 10.0 mA are available at energies up to 160 keV for routine production applications. The system has also been qualified for low current, low dose operation (1011 ions cm−2) and this unique versatility provides the Process and Equipment Engineers with a powerful new tool. The Model NV10-160 also utilizes the Nova-designed, double disk interchange processing system to minimize inactive beam time so that wafer throughputs, up to 300 wafers/h, are achievable on a routine basis. DatalockTM, a computer driven implant monitoring system and AT-4, the Nova cassette-to-cassette wafer loader, are available as standard options. As a production machine, the Model NV10-160 with its high throughput capability, will reduce the implant cost per wafer significantly for doses above 10 × 1015 ions/cm2. Performance patterns are now emerging as some twenty-five systems have now been shipped. This paper summarizes the more important characteristics and reviews the major design features of the NV10-160.

Advanced ion beam equipment used for semiconductor production

Abstract The ability to control energy, species and species purity, as well as intensity makes ion beam technology of great importance for surface analysis, and for material modification where the modest mass transfer does not create a limitation. The range of energy available extends from a few electron volts to megavolts. Some types of equipment have already seen considerable development such as the ion implanter, MBE systems with ion enhancement and ion beam microlithography tools. Yet it is clear that further improvements will be required if this equipment is not to limit the progress of the semiconductor industry. The status of ion implantation equipment will be reviewed and directions of research leading to equipment improvement will be indicated.

Implantation at energies above 150 keV

Abstract As is well known, implantation is used mostly at low energies to modify the surface region of semiconductor materials. If the implanted energy is high enough, the implanted ions lie well below the surface leaving it essentially unchanged, but creating a more conducting or more insulating layer at a deeper level. For example, implantation of high doses of oxygen ions ( ≈ 10 18 cm 2 ) can create a SiO2 barrier between the crystalline surface layer and the bulk of the substrate. On the other hand, a deep phosphorous implant through a masked surface can produce active source/drain elements for a semiconductor device. Interest in implants of this type is growing. This has developed a need for new types of implanters which are not limited in energy by the insulating strength of air. Two very different technologies are being successfully used to develop such machines, the linac and the tandem accelerator.