双面二维硅微条探测器的沾污失效分析及修复

硅微条探测器通过微电子工艺制作,易因沾污导致性能下降甚至失效;裸露的键合引线,也易因机械力形成隐性或显性失效。对上述现象的研究可用于修复、维护探测器并在设计和工艺流程中改进其性能。本文通过光学、电气手段分析其结构和制作工艺流程,根据沾污性质在不同条件下清洗探测器,中测后根据芯片图形、封装方式和电气要求修复探测器,最后采用同位素α能谱测试修复效果。对一块沾污后失效(无法加载偏压)的硅微条清洗后在大气环境,N面接地,P面加载负偏压条件下进行了测试,结果显示:170 V全耗尽,平均漏电流2.94μA,5.486 MeV的α峰能量分辨率约1.28%。失效键合所在条的另一面各条能谱观测到假峰,键合修复后消除。因沾污失效的硅微条探测器经过合适的清洗、修复,部分可以恢复性能,但清洗对表面和结构有损伤,须谨慎。另外,键合失效后,因信号不能引出导致的电荷积累会通过电容效应影响其它灵敏区。文章提示,探测器应存放于洁净,恒温,低湿度,避光,避强电磁干扰的环境,以提高能量和位置分辨率,并增加工作稳定性,延长使用寿命。

Contamination failure analysis and repairing for double side two dimensional silicon microstrip detectors

Silicon micro-strip detectors are fabricated by a micro-electronic process. Their performance will become worse, even failure when they suffer from various contaminations. Moreover, the naked bond wires are also easily disabled by external forces. The research for above mentioned events is available to repair and maintain these detectors, and to improve their performance. This paper analyses the detectors' structure and fabrication process, and cleans them in different conditions according to the characters of contamination. After a measurement, it repairs them based on the chip graphics, packaging means and the electronics demand. Finally, the α isotope energy spectrum is used to measure the repaired detectors. A repaired detector shows that when the N-side is earthed and the P-side is biased negative 170 V, the detector is depleted and its average leakage current is 2.94 μA. By bonding again, the ghost peaks in the energy spectra caused by the strips whose bond wire is invalid on the other side are eliminated. The results also indicate that most disabled detectors can be revived by reasonable cleaning and repairing, but the cleaning might damage the surface or structure of the detector, so it must be careful and not frequently. Furthermore, when a bond wire is invalid, the electric charge could not be led out, so they are accumulated and influence other sensitive region by charge effect. It points out that the detector should be stored a place in cleaning, thermostatic and low-humidity conditions and without light and strong electromagnetic waves. these methods would be beneficial to improving their energy resolution, position resolution ,stability and working life.