Low-Temperature Preparation and Properties of Ferroelectric Thin Films Using Excimer UV Irradiation

Bi4Ti3O12(BIT)铁电薄膜在非易失性铁电随机存储器(NvFRAM)中的应用得到了广泛的研究。与SrBi2Ta2O9(SBT)及其相关材料相比，BIT薄膜具有结晶温度低、结晶度高、剩余极化(P_R)大、矫顽场(E_C)小、居里温度(T_C)高等特点。然而，多晶BIT薄膜的Pr值低至约7-10μC/cm^2。最近，稀土(Ln=La，Pr，Nd和Sm)掺杂的BIT薄膜得到了广泛的研究。尤其是BiT；4-x&gt；NdxTi3O；12&gt；(BNT)薄膜由于其优异的铁电性能而备受关注。本工作采用化学溶液沉积法(Csd)m…研究了(BiNd4Ti3O；12&gt；(Bit)铁电薄膜的化学溶液沉积工艺和性能更多的方法是使用准分子紫外线灯。研究了准分子紫外光辐照对沉积的BNT前驱体薄膜晶化和微结构的影响。采用金属-有机溶液旋涂技术在铂(200 Nm)/TiOx(50 Nm)/SiO_2/Si衬底上沉积了BNT前驱体薄膜。在氧气气氛中对沉积的BNT前驱体薄膜进行准分子紫外光照射，可以有效地去除BNT薄膜中的有机物，提高薄膜的铁电性能。在准分子紫外光照射下制备的BNT薄膜具有无规则的取向，具有较强的(117)面反射，均匀的微结构由100-150 nm的颗粒尺寸组成，表面光滑。BNT薄膜经准分子紫外光辐照后，在550℃的低温下晶化，呈现出饱和的P-E磁滞回线，其Pr为12.7μC/cm~2，E_c为88 kV/cm~2，表现出较好的耐疲劳性能(最高可达109次)和良好的漏电流特性(小于3×10~(-7)&gt；)。较少

Ferroelectric Bi_4Ti_3O_<12> (BIT) thin films are extensively investigated for applications in nonvolatile ferroelectric random access memories (NvFRAM). Compared with SrBi_2Ta_2O_9(SBT) and its related materials, BIT thin films are known to crystallize at low processing temperature with a high crystallinity and to have a large remanent polarization (P_r), a small coercive field (E_c) and a high Curie temperature (T_c). However, P_r values of polycrystalline BIT thin films were seen to be as low as approximately 7-10 μC/cm^2. Recently, rare-earth (Ln=La, Pr, Nd and Sm)-doped BIT (BLnT) thin films have been intensively investigated. In particular, Bi_<4-x>Nd_xTi_3O_<12> (BNT) thin films have been attacting great attention for their ferroelectric properties which are superior to other rare earth-doped BIT thin films.In this work, chemical solution processing and properties of ferroelectric (Bi, Nd)_4Ti_3O_<12> (BIT) thin films were investigated by the chemical solution deposition (CSD) m … More ethod using excimer UV lamp. The effects of excimer UV irradiation to as-deposited BNT precurosor films on crystallization, microstructure.BNT precursor films were deposited on Pt(200nm)/TiO_x(50nm)/SiO_2/Si substrates by the spin-coating technique using metal-organic solutions. The excimer UV irradiation onto as-deposited BNT precursor films in O2 atmosphere was greatly effective in removing organic species of the BNT thin films and improving the ferroelectric properties. The synthesized BNT thin films using excimer UV irradiation showed a random orientation with a strong (117) reflection and a homogeneous microstructure consisting f grain sizes of 100-150 nm with a smooth surface. BNT thin films crystallized at a low temperature of 550℃ through the excimer UV irradiation process and showed a well-saturated P-E hysteresis loop with a P_r of 12.7 μC/cm^2 and E_c of 88 kV/cm.Their films exhibited a relatively good fatigue endurance up to 10^9 cycles and a good leakage current property with less than 3 x 10^<-7>. Less