磁控溅射结合脉冲激光制备钛掺杂硅薄膜的研究（英文）

Study of Titanium-doped Silicon Films Prepared by Magnetron Sputtering and Nanosecond Pulsed Laser

发展了一种改进的新型超掺杂工艺,通过真空磁控溅射多层镀膜后结合532nm波长可见纳秒脉冲激光熔融处理,进行超掺杂钛的硅薄膜材料的制备,并对材料的超掺杂层的性质和红外吸收性能进行了探究.结果表明,硅膜层中掺杂的钛原子的百分比浓度超过1%左右,对应钛原子浓度约为5×10^(20) cm^(-3)左右,超过钛在硅中形成超掺杂所对应的原子浓度.钛超掺杂层的厚度超过200nm左右,相对传统工艺具有明显提升,并且钛原子的浓度变化范围不超过20%,分布比较均匀.小角度X射线衍射测试表明经过可见脉冲激光熔融处理后的硅薄膜层材料结晶度为25%左右,呈多晶结构.同时红外吸收谱测试表明,样品的钛掺杂硅膜层在大于1 100nm波长的区域具有很高的红外吸收效果,最高的红外吸收系数达到1.2×10~4 cm^(-1),远超过单晶硅材料.具有比较明显的亚能带吸收的特征,呈现出Ec-0.26eV的掺杂能级.霍尔效应测试表明硅膜层具有较高的载流子浓度,超过了8×10^(18)cm^(-3).

An improved hyper-doping process has been developed which combines the vacuum magnetron sputtering coating and the 532 nm wavelength visible nanosecond pulse laser melting to prepare the silicon thin films of titanium doping.The characteristics of hyper-doped layer and the infrared light absorption properties of silicon thin film were studied.The X-ray photoelectron spectroscopy shows that the titanium concentration of doping layer of sample is more than 1%(the corresponding titanium atom concentration is about 5×10^20 cm^-3),higher than the hyper-doping concentration of titanium in silicon.And the thickness of hyper-doping layer is more than 200 nm which improves obviously compared with traditional technology.The variable range of the concentration of titanium atoms is not more than 20%,and the atom distribution is more homogeneous.The glancing incidence X-ray diffraction pattern shows that the crystallinity of the silicon thin film layer is polycrystalline structure and about 25%around after pulsed laser melting.At the same time,the infrared light absorption measurement shows that the hyper-doping silicon thin film has high infrared absorptivity in wavelength larger than 1 100 nm.The highest infrared light absorption coefficient of sample is almost to 1.2×10^4 cm^-1,which is far more than that of monocrystalline silicon.The material has obvious characteristics of sub-band absorption and shows a donor impurity energy level of the Ec-0.26 eV.The Hall effect measurement shows that the thin film layer has high carrier concentration,over 8×10^18 cm^-3.The Hall effect measurement shows that the thin film layer has high carrier concentration,over 8×10^18 cm^-3.