Amethyst Technologies (United States)

The N-related isoelectronic centers in dilute nitrides act as localized states inside the band gap. Here, hydrogenation is shown to reduce the number of defect levels. However, some residual defects persist, and their nature remains relatively unexplored. Using density functional total energy calculations, we show that the N–In complex may cause some of the residual defect levels evident in these materials. Moreover, these N–In effects can be neutralized through hydrogenation in a similar manner to that of the N–Ga complex. The calculated formation energies suggest the inherent stability of the N–In defect complexes and In-rich alloy fluctuations in dilute nitrides.

A model is proposed to explain disparities found in the operability values and histograms for long-wavelength infrared HgCdTe focal-plane arrays fabricated on Si substrates compared with those fabricated on CdZnTe. The starting point for the model is the close agreement between the aerial density of discrete species (particles, contamination spots, crystalline defects on Si surface) in various interfaces in the HgCdTe/CdTe/Si structure and the density of failed pixels in the array. The density of discrete species is acquired by applying a newly developed variation of the secondary-ion mass spectrometry (SIMS) depth-profiling technique to samples that have been deuterated to enhance detection. A mechanism of selective activation of threading dislocations in a HgCdTe layer on Si is proposed to link discrete species with failed detector pixels.

A thin film of Ge-rich Ge x Si1−x on a (100) Si substrate was synthesized by ion implantation followed by thermal oxidation. Proper oxidation conditions were maintained to produce a film with Ge atomic content of more than 95%, confirmed by both high-resolution Rutherford backscattering spectrometry (RBS) and Raman spectroscopy. The strain state of the Ge-rich thin film is a function of its thickness, as determined by the implantation fluence. The use of Raman spectroscopy to monitor the composition and strain state of the Ge thin film formed is discussed.

This paper discusses advantages and disadvantages of smaller transfer batch size in an automated semiconductor factory. A framework is suggested by which the theoretical cycle time is determined from the point-of-view of the wafer, not the lot. Using this framework, we then look at the possible application of a virtual cluster tool by identifying requirements on the process times and transport system. Benefits and risks are then discussed for the approach, using a simple example

In this study, we verify the performance of the simultaneous equations method using an experimental active noise control system. The simultaneous equations method is based on a priciple different from the filtered-x algorithm requiring a filter modeled on a secondary path from a loudspeaker to an error microphone. Instead of the filter, called the secondary path filter, this method uses an auxiliary filter identifying the overall path consisting of a primary path, a noise control filter and the secondary path. As inferred from the configuration of the overall path, the auxiliary filter can provide two independent equations when two different coefficient vectors are given to the noise control filter. The method thereby estimates the coefficient vector of the noise control filter minimizing the output of the error microphone. In this paper, we propose the application of a frequency domain adaptive algorithm to the identification of the overall path. An improvement in the noise reduction speed is thereby expected. In this paper, we also present computer simulation results demonstrating that the simultaneous equations method can automatically recover the noise reduction effect degraded by path changes, and finally, using an experimental system, we indicate that the method successfully works in practical systems.

This paper discusses the use of a CFD (computational fluid dynamics) code for the design and optimization processes of a minienvironment mounted on a wafer process tool. The three-dimensional code was used to predict the air velocity flied and pressure distribution in the minienvironment based on a finite volume approach. The geometric model consists of the minienvironment, the tool surface, and the integrated I/O Indexer interfaces. The airflow in the minienvironment (with a conceptual design configuration) was simulated. The results prompted a design change. The new design has a desirable airflow for a more effective minienvironment performance. Particular attention was paid to air recirculation zones that could potentially trap particles generated during the process and to maintaining a positive differential pressure to prevent cross contamination. CFD was shown to be an important step in the design process.