重掺杂多晶硅薄膜中磷氧化物的探究  

Phosphorus oxides in heavily doped polysilicon films

作　　者：王艺琳 兰自轩 杜汇伟 赵磊[1] 马忠权[1] Wang Yi-Lin;Lan Zi-Xuan;Du Hui-Wei;Zhao Lei;Ma Zhong-Quan(SHU-SOEN’s R&D Lab,Department of Physics,Shanghai University,Shanghai 200444,China;College of Materials and Chemistry,China Jiliang University,Hangzhou 310018,China)

机构地区：[1]上海大学物理系,上海大学索朗光伏材料与器件R&D联合实验室,上海200444 [2]中国计量大学材料与化学学院,杭州310018

出　　处：《物理学报》2022年第18期356-362,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61874070,61674099,61274067);上海大学索朗光伏材料与器件R&D联合实验室基金(批准号:SS-E0700601)资助的课题。

摘　　要：在n-型隧穿氧化物钝化接触(n-TOPCon)光伏器件中,高浓度磷掺杂的多晶硅薄膜(n^(+)poly-Si)是电子选择性钝化的关键材料.它的光学和电子学性能取决于化学组态与多晶结构的物相,并依赖于晶态转化过程中的高温退火与结构弛豫.采用低压化学气相沉积技术在SiO/n-Si衬底上生长制备poly-Si(n^(+))薄膜,利用带有深度刻蚀特征的X-射线光电子能谱、高分辨率透射电子显微术和X-光衍射分析方法,研究了该薄膜的微结构.发现薄膜中氧(O)元素的O 1s态的两个拟合峰(O2和O3)的结合能分别为532.1 eV和533.7 eV,对应O—Si和O—P的成键态;而磷(P)元素的P 2p态的两个拟合峰(P2和P3)的结合能分别为132.4 eV和135.1 eV,对应着O—P^(*)的同根成键态.电子显微与光衍射分析表明,该多晶硅薄膜具有(111)晶向择优生长的特点,晶面间距为0.313 nm,平均晶粒尺寸在43.6—55.0 nm.而(111)晶面簇在920℃高温退火过程中,产生力学形变与晶界,在局域范围内呈现大晶粒的单晶态.结合热力学函数,如生成焓、反应熵、热容、形成能与吉布斯自由能,以及能量最低原理分析可知,多晶硅薄膜内存在O—Si和O—P键形成的条件,产生了氧化硅和氧化磷的成键态.In tunneling oxide passivation contact(n-TOPCon)photovoltaic devices,poly-Si(n^(+))films with highconcentration phosphorus doping are the key materials for electron selective passivation.Its optical and electronic properties strongly depend on the chemical configuration and physical phase,and also on high temperature annealing and structural relaxation in the recrystallization process.The poly-Si(n^(+))films grown on SiO_(x)/n-Si substrates by low pressure chemical vapor deposition technology are investigated,while the microstructure of the film is studied by using X-ray photoelectron spectroscopy with depth etching,highresolution transmission electron microscopy and X-ray diffraction analysis.It is found that the binding energy values of the two fitted peaks(O2 and O3)of O 1s state of the thin film are situated at 532.1 and 533.7 eV,corresponding to the bonding of O—Si and O—P,respectively.The binding energy values of the two fitted peaks(P2 and P3)of P 2p state are located at 132.4 and 135.1 eV,corresponding to O—P^(*) bonding with the same origin.Electronic microscopy and light diffraction analyses show that the polycrystalline silicon film has the characteristic of(111)preferential orientation,and the space of crystal plane is 0.313 nm,for which the average grain size is in a range of about 43.6–55.0 nm.However,the mechanical deformation and grain boundaries are generated in the annealing process at 920℃along(111)crystal cluster,resulting in the localized monocrystalline state within large grains.The comprehensive analyses of thermodynamic function parameters of formation enthalpy,reaction entropy,heat capacity,formation energy and Gibbs free energy and energy minimum principle analysis indicate that there exist conditions for forming Si—O and P—O bonds in the polysilicon film,and thus the bonding state of silicon and phosphorus oxides are formed.

关 键 词：多晶硅(n^(+)) 磷氧化物 硅氧化物 光电子谱 深度刻蚀分析 

分 类 号：TQ127.2[化学工程—无机化工] TB383.2[一般工业技术—材料科学与工程]