| Abstrakt: |
We have reviewed fundamental and application issues of the UST method in various semiconductors and electronic devices: single and compound materials; crystalline, polycrystal-line, and amorphous; as-grown and processed wafers. Numerous ultrasonic-controlled defect reactions were observed and explored. Examples of a significant UST effect to enhance the point defect gettering and defect passivation with atomic hydrogen exhibit a strong potential for the UST technology to be utilized as a defect engineering tool. After comprehensive study, UST mechanisms enabled the development of a reliable methodology and apparatus for using the UST in microelectronics and optoelectronics. Feasibility projects performed on semiconductor devices established a statistically valid database for applying this technique to benefit device performance. Although the core of UST technology-the generation of ultrasound into electronic material-is a common feature for various UST applications, a specific LTST recipe has to be developed for each individual type of material or device. Such a recipe is comprised of a synergetic combination of the optimal IJST parameters: temperature, amplitude, duration, and resonance frequency. Additionally, UST processing can be performed concurrently or consecutively with UV or IR light, under a pulsed electric field or laser activation, arid so on. This illustrates a high level of flexibility of the UST technology, its compatibility with different stages of device fabrication, and an easy adjustment to a particular device problem. Although UST has not yet found a commercial niche in a broad variety of potential applications, one can predict that the time is near when UST technology will be an effective means for defect engineering in semiconductors. [ABSTRACT FROM AUTHOR] |
