SCIENCE CHINA Physics, Mechanics & Astronomy © Science China Press and Springer-Verlag Berlin Heidelberg 2010 phys.scichina.com www.springerlink.com *Corresponding author (email: clwangee@163.com)  Research Paper  January 2010 Vol. 53 No.1: 111−115 doi: 10.1007/s11433-010-0084-3 Poly-Si films with low aluminum dopant containing by aluminum-induced crystallization WANG ChengLong 1,2* , FAN DuoWang 1,2* , WANG ChengBin 2 , GENG ZhongRong 2 , MA HaiLin 2 & MIAO ShuFan 1 1 National Engineering Research Center for Technology and Equipment of Green Coating, Lanzhou Jiaotong University, Lanzhou 730070, China; 2 MOE Key Laboratory of Opto-electronic Technology and Intelligence Control, Lanzhou Jiaotong University, Lanzhou 730070, China Received January 8, 2009; accepted February 2, 2009 Typically, highly p-doped (2×10 18 cm −3 ) poly-Si films fabricated by the aluminum induced layer exchange (ALILE) process are not suitable for solar cell absorber layers. In this paper, the fabrication of high-quality, continuous polycrystalline silicon (poly-Si) films with lower doping concentrations (2×10 16 cm −3 ) using aluminum-induced crystallization (AIC) is reported. Secondary-ion-mass spectroscopy (SIMS) results showed that annealing at different temperature profiles leads to a variety of Al concentrations. Hall Effect measurements revealed that Al dopant concentration depends on the annealing temperature and temperature profile. Raman spectral analysis indicated that samples prepared via AIC contain some regions with small grains. polycrystalline silicon, low doping concentration, AIC, crystallization The crystallization of amorphous silicon (a-Si) deposited on glass substrates is gaining increasing interest for its impor- tance in polycrystalline silicon (poly-Si) thin film solar cells [1]. One of the most important challenges for the develop- ment of polycrystalline silicon (poly-Si) thin film solar cells on glass substrates is the growth of crystalline silicon at low-temperature. A promising means to overcome this problem is the deposition of a-Si followed by subsequent low-temperature crystallization. The crystallization tech- niques that attracting most attention so far have been the solid phase crystallization (SPC) [2], laser crystallization (LC) [3], and rapid photo-thermal crystallization (RTP) [4]. As an alternative approach, metal-induced crystallization (MIC) has caught considerable interest, because the crystal- lization temperature of a-Si are much lower than reported temperature for SPC of a-Si of about 600°C. When a-Si is in contact with certain metal, remarkably, the crystallization temperature is well below the eutectic temperature of the corresponding metal/Si system [5]. In MIC of silicon, the silicide forming and nonsilicide forming crystallization is distinguishable. In contrast to compound forming systems (e.g. Ni/Si, Cu/Si, and Ag/Si, etc.), simple eutectic systems, such as Al/Si (AIC), do not form stable silicides [6]. The Al/Si system does not form a stable silicide; a lower crystal- lization temperature can be achieved [7]. For Al/Si system, the crystallization temperatures as low as 100°C has been reported [8]. The mechanism for AIC is the alumi- num-induced layer exchange (ALILE) process which was first introduced by Nast et al. [9]. Annealing of a glass/Al/a-Si composite layer at temperature below the eutectic temperature of the Al/Si system (577°C) leads to the formation of a glass/poly-Si/Al(+Si) composite layer. During the annealing, silicon atoms diffuse into the alumi- num layer and then nucleate in the aluminum matrix. The nuclei grow in all directions until confined within the alu- minum layer between the glass and the a-Si layer. Crystal growth then continues in a lateral direction only until adja- cent crystallites form a continuous poly-Si layer. The