Mechanism Investigations and Control of Phonon-Excitation Anneal Process for Ultra-Shallow Junction Formation

超浅结(10-30 nm)的形成是制造下一代超大规模集成电路(ULSI)器件所必需的。最先进的掺杂激活技术是基于热过程的，例如快速热退火(RTA)和表面熔化的激光热退火，这些过程受到热预算的限制，导致杂质向更深的区域和/或横向扩散。本研究通过直接激发声子和/或原子间键态来研究浅区注入杂质的非平衡(非热)退火过程，这是一种有效的低温形成超浅结的技术。主要成果总结如下。1)Pomp-Probe反射率测量表明，超短脉冲激光辐照引起声子振动，随后光激发载流子弛豫，其中声子振动随激光强度的增加而非线性增强。2)高分辨率的横截面电子显微镜观察证实了超短脉冲激光辐照下注入层的再结晶成功。3)注入层的方阻受激光辐照条件的控制，其中方阻与原子尺度的纳米结构密切相关。4)方阻低至400欧姆/平方英尺的可行性。对注入0.5keV B的样品证实了这一点。5)作为激光辐照后控制缺陷的有效表面激发工艺之一，等离子体技术被发展用于大面积非平衡等离子体的产生和控制，其中300 mm晶片工艺的可行性得到了论证。

Formation of ultra-shallow junctions (10-30 nm) is required for fabrication of CMOS devices in next-generation ULSIs. State-of-the-art technologies for the dopant activation are based on thermal processes such as rapid thermal annealing (RTA) and laser thermal annealing with surface melting, which are constrained by the thermal budget to cause unwanted transient diffusion of the dopants into deeper region and/or in lateral direction. This research has been carried out to investigate the non-equilibrium (non-thermal) anneal processes of the implanted dopants in the shallow region by directly exciting phonons and/or interatomic bonding states as one of the effective low-temperature formation technology of the ultra-shallow junctions. Major results are summarized as follows. 1) Pomp-probe reflectivity measurements showed that the ultra-short pulse laser irradiation induced phonon vibrations followed by relaxation of the optically excited carriers, in which the phonon vibration was enhanced nonlinearly with laser intensities. 2) Cross-sectional high-resolution TEM observations confirmed successful re-crystallization of the implanted layer by the ultra-short pulse laser irradiation. 3) Sheet resistance of the implanted layer was controlled by the laser irradiation conditions, in which the sheet resistance was confirmed to show close correlation with the atomic-scale nanostructure. 4) Feasibility of the sheet resistance as low as 400 ohms/sq. was demonstrated for the 0.5-keV B implanted samples. 5) As one of the effective surface excitation processes to control defects after the laser irradiation, plasma technologies were developed for generation and control of the large-area non-equilibrium plasmas, in which feasibility of the 300-mm wafer processes was demonstrated.