扩散后冷却效应对高纯锗中霍尔法得到的活性锂施主分布的影响
Post-diffusion cooling effects on Hall-derived active lithium donor profiles in high-purity germanium
中文总结 AI 辅助
该研究探究了高纯锗探测器锂扩散后冷却工艺对活性锂施主分布的影响，采用霍尔效应测量等方法明确了短、长冷却对施主分布参数的差异，为探测器制造优化提供了依据。
中文摘要 AI 辅助
锂（Li）扩散常用于在高纯锗（HPGe）探测器中形成n⁺接触，但最终的电活性施主分布可能对扩散后的热历史敏感。本研究采用油基锂悬浮液将锂引入高纯锗试样中，在240至310℃的标称温度下扩散30分钟。通过测量见证锗的冷却历程，记录了短冷却和长冷却两种工艺方案。结合逐层材料去除与77K下的霍尔效应测量，重构了差分推导的表观霍尔施主分布。由于非均匀导电层中的霍尔响应受迁移率加权，这些分布是可操作的电活性施主度量，而非直接的局部锂浓度或总锂浓度分布。采用互补误差函数拟合，得到外推表观截距Nₛ,app和表观分布宽度参数Dₐₚₚ。对于所研究的试样，短冷却对应更大的Nₛ,app和更陡峭的分布，而长冷却对应更低的Nₛ,app和更宽的低浓度尾。拟合得到的浓度阈值深度对于长冷却试样也延伸到锗体内部更远的位置。这些结果表明，在为HPGe探测器制造参数化霍尔活性锂扩散n⁺接触时，应考虑完整的扩散后热历史。
英文摘要
Lithium (Li) diffusion is commonly used to form $n^{+}$ contacts in high-purity germanium (HPGe) detectors, but the final electrically active donor profile can be sensitive to the post-diffusion thermal history. Li was introduced into HPGe coupons using a lithium-in-oil suspension and diffused for $30~\mathrm{min}$ at nominal temperatures of $240$--$310~^{\circ}\mathrm{C}$. Short- and long-cooling protocols were documented by measured witness-Ge cooling histories. Sequential material removal combined with Hall-effect measurements at $77~\mathrm{K}$ was used to reconstruct difference-derived apparent Hall donor profiles. Because Hall response in a nonuniform conducting layer is mobility weighted, these profiles are operational electrically active-donor metrics rather than direct local or total-Li concentration profiles. Complementary-error-function fits were used to obtain the extrapolated apparent intercept $N_{s,\mathrm{app}}$ and the apparent profile-width parameter $D_{\mathrm{app}}$. For the coupons studied, short cooling was associated with larger $N_{s,\mathrm{app}}$ and sharper profiles, whereas long cooling was associated with lower $N_{s,\mathrm{app}}$ and broader low-concentration tails. Fit-derived concentration-threshold depths likewise extended farther into the Ge bulk for the long-cooling coupons. These results show that the complete post-diffusion thermal history should be considered when parameterizing Hall-active Li-diffused $n^{+}$ contacts for HPGe detector fabrication.
