标题： 高电阻外延层 0.18 微米工艺生产的 CMOS 像素传感器的带电粒子探测性能 显示英文标题

标题： Charged particle detection performances of CMOS pixel sensors produced in a 0.18 um process with a high resistivity epitaxial layer

摘要： CERN 的 ALICE 实验装置将在 2017/18 年期间 LHC 的第二次长停机（LS2）期间进行升级。 此次升级的主要动机之一是将粲夸克和底夸克粒子的物理研究范围扩展到低横动量区域。 这需要显著提高 ALICE 内部跟踪系统 (ITS) 的空间分辨率和数据率能力。 为了实现这一目标，新的 ITS 将配备厚度为 50 微米的 CMOS 像素传感器 (CPS)，覆盖探测器的 3 个最内层或全部 7 层。 为 ITS 升级开发的 IPHC（斯特拉斯堡）CPS 是基于为 RHIC 的 STAR-PXL 开发的 MIMOSA 28 传感器，在 0.35 微米 CMOS 工艺中制造的。 为了满足 ITS 升级在读出速度和抗辐射性能方面的要求，应采用特征尺寸减小且高电阻外延层的 CMOS 工艺。 在这方面，借助第一个原型芯片 MIMOSA 32，研究了 TowerJazz 0.18 微米 CMOS 工艺的带电粒子检测性能和抗辐射性能。 在 CERN-SPS 使用 120 GeV/c 负π介子进行的束流测试允许测量非辐照芯片的信噪比 (SNR)，范围在 22 到 32 之间，具体取决于像素设计。 经过 1 MRad 和 10^13 n_eq/cm^2 组合剂量辐照的芯片，在冷却温度从 15°C 变化到 30°C 时，观察到 SNR 范围在 11 到 23 之间。这些 SNR 值被测量为在辐照前后的粒子探测效率分别超过 99.5% 和 98%。 这些令人满意的结果验证了 TowerJazz 0.18 微米 CMOS 工艺适用于 ALICE ITS 升级。 显示英文摘要

摘要： The apparatus of the ALICE experiment at CERN will be upgraded in 2017/18 during the second long shutdown of the LHC (LS2). A major motivation for this upgrade is to extend the physics reach for charmed and beauty particles down to low transverse momenta. This requires a substantial improvement of the spatial resolution and the data rate capability of the ALICE Inner Tracking System (ITS). To achieve this goal, the new ITS will be equipped with 50 um thin CMOS Pixel Sensors (CPS) covering either the 3 innermost layers or all the 7 layers of the detector. The CPS being developed for the ITS upgrade at IPHC (Strasbourg) is derived from the MIMOSA 28 sensor realised for the STAR-PXL at RHIC in a 0.35 um CMOS process. In order to satisfy the ITS upgrade requirements in terms of readout speed and radiation tolerance, a CMOS process with a reduced feature size and a high resistivity epitaxial layer should be exploited. In this respect, the charged particle detection performance and radiation hardness of the TowerJazz 0.18 um CMOS process were studied with the help of the first prototype chip MIMOSA 32. The beam tests performed with negative pions of 120 GeV/c at the CERN-SPS allowed to measure a signal-to-noise ratio (SNR) for the non-irradiated chip in the range between 22 and 32 depending on the pixel design. The chip irradiated with the combined dose of 1 MRad and 10^13 n_eq/cm^2 was observed to yield a SNR ranging between 11 and 23 for coolant temperatures varying from 15 C to 30 C. These SNR values were measured to result in particle detection efficiencies above 99.5% and 98% before and after irradiation respectively. These satisfactory results allow to validate the TowerJazz 0.18 um CMOS process for the ALICE ITS upgrade.