SBIR Phase I: New Thin N+ Contacts for Germanium Detectors

这个小企业创新研究第一阶段项目将对磷注入和脉冲准分子激光退火步骤进行深入研究，以使这种方法成为在大型HPGe探测器上生产薄n+触点的商业可行工艺。高纯锗（HPGe）探测器是高分辨率x射线和y射线光谱中应用最广泛的设备，目前这些探测器在核物理、环境监测、高能物理实验、材料科学研究、地球物理勘探和y射线天文学等多种应用中得到了广泛的应用。锗技术长期存在的问题之一是缺乏薄的n+型接触，这阻碍了对p型锗晶体的低能x射线具有高探测效率的探测器的制造。解决这个问题很重要，因为p型材料通常比n型材料便宜，而且更容易大批量生产。此外，p型探测器在近端同轴结构中比n型探测器具有更好的电荷收集性能。最近，该公司通过在锗中植入磷，然后使用脉冲激光退火去除植入损伤，成功地在HPGe探测器上制备了薄的n+型触点。所提出的触点的成功制造将增加p型锗探测器可以使用的能量范围，也将允许制造复杂的探测器设计，如单片阵列。因此，具有新n+触点的高能锗探测器可用于核物理、天文学、环境监测、同步加速器研究、核保障与核查以及地球物理勘探等领域。

This Small Business Innovation Research Phase I project will perform an in-depth investigation of the phosphorus implantation and the pulsed excimer laser annealing steps in order to make this approach a commercially viable process for producing thin n+ contacts on large HPGe detectors. High purity germanium (HPGe) detectors are the most widely used devices for high resolution X-ray and y-ray spectroscopy, and these detectors are currently used in diverse applications such as nuclear physics, environmental monitoring, high energy physics experimentation, materials science studies, geophysical exploration, and y-ray astronomy. One of the long standing problems in the germanium technology is the lack of a thin n+-type contact, which prevents fabrication of detectors with high detection efficiency for low energy X-rays from p-type germanium crystals. It is important to solve this problem because p-type material is generally cheaper than n-type material and is more readily available in larger volumes. Also, p-type detectors have better charge collection properties in close end coaxial structures than n-type detectors. Recently, this firm has successfully produced thin n+-type contact on HPGe detectors by implanting phosphorus in germanium, and then using pulsed laser annealing to remove implantation damage. Successful fabrication of the proposed contacts would increase the energy range over which p-type germanium detectors can be used and would also allow fabrication of complex detector designs such as monolithic arrays. Thus the HPGe detectors with our new n+ contacts can be used in nuclear physics, astronomy, environmental monitoring, synchrotron studies, nuclear safeguards and verification, and geophysical exploration.