Charge multiplication in irradiated segmented silicon detectors with special strip processing-猫眼课题宝

采用特殊条带处理的辐照分段硅探测器中的电荷倍增

DOI：

10.1016/j.nima.2012.04.033

发表时间：

2013

期刊：

Accelerators, Spectrometers, Detectors and Associated Equipment

影响因子：

通讯作者：

中科院分区：

文献类型：

作者：

Casse G

在严重辐照的硅探测器中，电荷倍增现在是一个得到充分证明的效应，它可以增强它们的电荷收集，使它们的可操作性达到未来超级对撞机（如欧洲核子研究中心的高亮度LHC）预期的剂量。这种影响有很好的文献记载，但并不完全清楚。倍增是由碰撞电离引起的，由于热电子在高电场中移动，该高电场在被照射的传感器中的结附近发展。由于强子辐照硅体中不均匀的有效空间电荷的空间分布未知，因此无法获得硅体中电场分布的详细信息。有效空间电荷分布的梯度对于发生倍增的高电场区域的形成至关重要。电场可能受到形成n-p结的注入物和结附近的非均匀体空间电荷的影响。深n+结构（结）可以增强或降低倍增效应。此外，改变的掺杂梯度（例如可通过结和p体之间的分级p掺杂获得）可以实现相同的结果。为了实现微带探测器中增强的电荷倍增，通过深p掺杂扩散和在硅体中蚀刻的沟槽以及用n+掺杂多晶硅填充以创建深结来成形结。我们在这里报告的结果与这些方法之前和之后的各种剂量的中子辐照。

Charge multiplication in severely irradiated silicon detectors is now a well proven effect that enhances their charge collection and makes them operable up to the doses anticipated for future super-colliders (like the high luminosity LHC at CERN). The effect is well documented but not completely understood. The multiplication is caused by impact ionisation due to hot electrons moving in the high electric field that develops near the junction in the irradiated sensors. The details of the electric field profile in the silicon bulk are not available due to the unknown spatial distribution of the inhomogeneous effective space charge in the hadron irradiated silicon bulk. The gradient of the effective space charge distribution is crucial for the formation of high electric field regions where the multiplication takes place. The electric field might be influenced by the implant forming the n–p junction and by a non-homogenous bulk space charge near the junction. Deep n+structures (junction) could enhance or reduce the multiplication effect. Also an altered doping gradient (obtainable for example by a graded p-doping between the junction and the p-bulk) could achieve the same results. In order to achieve enhanced charge multiplication in microstrip detectors the junction has been shaped by mean of deep p-doping diffusion and of trenches etched in the silicon bulk and filled with n+doped polysilicon to create a deep junction. We report here the result obtained with these methods before and after various doses of neutron irradiation.