A Non-Thermal Annealing Process Applied to Neutron Transmutation Doped Silicon

小行星9732092 该项目旨在研究和开发一种新的退火技术，该技术能够修复晶体的损伤并在不使用热能的情况下电激活硅中的掺杂剂。 退火是通过将高能激光脉冲聚焦到样品表面上的一个小点上来完成的。 实验表明，整个样品被退火，即使在远离激光焦点的区域。 据推测，激光在样品中发射冲击波，并且该波导致晶体退火。 由于激光脉冲很短（纳秒），预计该过程伴随着比热过程中发生的扩散少得多的扩散。 扩散是下一代高密度低功率器件的设计和制造中的限制因素之一。 如SIA所述，半导体工业的“关键需求”是开发用于低泄漏浅结的“最小退火”。 上述非热处理显然是这种“最小退火”的候选。 虽然该工艺对于设备制造中的一个步骤是有吸引力的，但必须首先回答一些基本问题。 两个最紧迫的问题涉及退火的最佳参数和退火发生的实际机制。 最佳参数的确定将允许该技术应用于各种不同的材料，并最终应用于图案化器件。 对退火机制的理解将进一步理解该项目的材料科学方面，并将有助于将该技术应用于不同的材料。 这些问题的答案将得到进一步的实验，改变退火过程中所涉及的参数，通过研究实现退火而不引入热能的交替方法，并通过模拟冲击波通过受损的晶格。 ***

9732092 Donnelly The project seeks to investigate and develop a new annealing technique that is able to both repair damage to a crystal and electrically activate dopants in silicon without the use of thermal energy. The annealing is accomplished by focusing a high energy laser pulse onto a small spot on the surface of the sample. Experiments have shown that the entire sample is annealed, even in regions far from the laser focal spot. It is speculated that the laser launches a shock wave in the sample, and that this wave causes the crystal to anneal. Because the laser pulses are short (nanoseconds), the process is expected to be accompanied by much less diffusion than occurs in thermal processes. Diffusion is one of the limiting factors in the design and fabrication of next-generation high density low power devices. A "critical need" for the semiconductor industry, as stated by SIA, is the development of a "minimum anneal" for low leakage shallow junctions. The above mentioned non-thermal process is clearly a candidate for this "minimum anneal". While the process is attractive for a step in device fabrication, there are fundamental questions that must first be answered. The two most pressing questions involve the optimum parameters for annealing, and the actual mechanism by which the annealing occurs. Determination of optimum parameters will allow the technique to be applied to a variety of different materials, and eventually to patterned devices. Understanding of the annealing mechanism will further understanding of the materials science aspects of the project, and will also assist in the application of the technique to different materials. The answers to these questions will be obtained by further experiments which vary the parameters involved in the annealing process, by investigating alternated methods of achieving annealing without the introduction of thermal energy, and by modeling the passage of a shock wave through a damaged crystal lattice. ***