热处理对富硅氧化硅薄膜中硅纳米晶形成的影响

采用磁控溅射法制备了富硅氧化硅薄膜, 然后分别经过一步热处理、两步热处理和快速热处理制备了镶嵌有硅纳米晶的氧化硅薄膜. 实验结果表明, 在硅含量为～ 42.63 at.%的富硅氧化硅薄膜中, 三种热处理均能形成10¹²/cm²量级的硅纳米晶. 其中在两步热处理中, 硅纳米晶的密度最高, 达到2.2× 10¹²/cm², 并且尺寸均匀、结晶完整性好; 一步热处理后的样品中, 硅纳米晶密度较低, 并且部分纳米晶结晶不充分; 快速热处理后的样品中, 硅纳米晶密度最低、尺寸分布不均匀, 并且存在孪晶结构. 分析认为, 热处理初始阶段的形核过程对纳米晶的密度及微观结构有着重要的影响, 两步热处理中的低温段促进了纳米晶的成核, 有助于形成高密度高质量硅纳米晶.

Effects of thermal treatments on the formation of nanocrystalline Si embedded in Si-rich oxide films

Silicon oxide films containing nanocrystalline Si（nc-Si） are fabricated by magnetron sputtering method followed by one-stepannealing, two-step-annealing and rapid thermal annealing（RTA）,separately.In silicon-rich oxide films containing～42.63 at.%of Si,dense nc-Si in a magnitude of 10¹²/cm^-2 are obtained in all of the samples subjected to three different thermal treatments.In the two-step-annealing sample,the density of nc-Si reachs a maximum(2.2×10¹²/cm^-2),and the nc-Si is well crystallized and uniform in size distribution.In the one-step-annealing sample,the density of nc-Si is silightly lower than in the two-step-annealing sample, and large deficiently crystallized nc-Si is observed in the sample.The RTA leads to the lowest density of nc-Si with the largest size distribution among the three samples.Moreover,large nc-Si formed by coalescence of small ones and twin crystals are also discovered in the RTA sample.It is believed that nucleation at the early stage of nanocrystal growth influences the density and the micostructure of nc-Si.The annealing at low temperature in the two-step-annealing facilitates the formation of new nulcei,which is beneficial to improving the quality and density of nc-Si.