(1. 河北大學(xué) 電子信息工程學(xué)院，保定 071002；
2. 河北大學(xué) 計(jì)算材料與器件模擬研究中心，保定 071002；
3. 河北大學(xué) 河北省數(shù)字醫(yī)療工程重點(diǎn)實(shí)驗(yàn)室，保定 071002；
4. 中國(guó)工程物理研究院 總體工程研究所，綿陽(yáng)621900)
摘 要: 采用基于密度泛函理論的第一性原理平面波超軟贗勢(shì)方法，計(jì)算本征以及P替位式摻雜，P間隙式摻雜4H-SiC的晶格常數(shù)、能帶結(jié)構(gòu)、態(tài)密度、載流子濃度和電導(dǎo)率。結(jié)果表明：P摻雜減小了4H-SiC的禁帶寬度，其中P替位C原子摻雜的禁帶寬度最小。替位式摻雜導(dǎo)致4H-SiC的費(fèi)米能級(jí)進(jìn)入導(dǎo)帶，使其成為n型半導(dǎo)體，間隙式摻雜使4H-SiC的費(fèi)米能級(jí)接近導(dǎo)帶并在其禁帶中引入雜質(zhì)能級(jí)。替位式摻雜后，4H-SiC的自由電子主要存在于導(dǎo)帶底，而間隙式摻雜4H-SiC中除了導(dǎo)帶底外，禁帶中的雜質(zhì)能級(jí)也提供了自由電子，因此，電子濃度大幅度增加。摻雜4H-SiC的載流子遷移率主要由中性雜質(zhì)對(duì)電子的散射決定，較本征態(tài)的大幅度降低。通過(guò)計(jì)算4種體系的電導(dǎo)率可知，P替位Si原子摻雜4H-SiC的電導(dǎo)率最大，導(dǎo)電性最好。
關(guān)鍵字: 4H-SiC；P摻雜；第一性原理；電導(dǎo)率
（1. College of Electronic and Informational Engineering, Hebei University, Baoding 071002, China;
2. Research Center for Computational Materials and Device Simulations, Hebei University, Baoding 071002, China;
3. Key Laboratory of Digital Medical Engineering of Hebei Province, Hebei University, Baoding 071002, China;
4. Institute of Systems Engineering, China Academy of Engineering Physics, Mianyang 621900, China）
Abstract:The lattice parameters, band structures, density of states, carrier concentrations and electrical conductivities of pure 4H-SiC, P substitutional doped, and P interstitial doped 4H-SiC were calculated using the plan-wave ultra-soft pseudo-potential method based on the density functional theory. The results indicate that the P doping decreases the forbidden band widths of 4H-SiC, and the P substituted for C doped 4H-SiC shows the narrowest band gap. Substitutional doping makes the Fermi energy level introduces into the conduction band of 4H-SiC, and the 4H-SiC becomes an n-type semiconductor. Interstitial doping makes the Fermi energy level near the conduction band of 4H-SiC and introduces impurity energy levels into the forbidden band. The electrons of substitutional doped 4H-SiC mainly exist at the bottom of the conduction band. While the impurity energy levels in the forbidden band also provides electrons except those existing at the bottom of the conduction band of interstitial doped 4H-SiC, so, the electron concentration increases significantly. The carrier mobility of the doped 4H-SiC is mainly depending on the neutral impurity scattering and decreases significantly comparing to the intrinsic state. Through the calculations of the electrical conductivities of the four systems, it is found that the electrical conductivity of 4H-SiC with P substituted for Si is the biggest, and the 4H-SiC shows the best conductivity.
Key words: 4H-SiC; P doping; first-principles; electrical conductivity
