软抛光垫条件下非晶态Ge2Sb2Te5的化学机械抛光

Chemical mechanical planarization（CMP） of amorphous Ge₂Sb₂Te₅（a-GST） is investigated using two typical soft pads（politex REG and AT） in acidic slurry.After CMP,it is found that the removal rate（RR） of a-GST increases with an increase of runs number for both pads.However,it achieves the higher RR and better surface quality of a-GST for an AT pad.The in-situ sheet resistance（R_s） measure shows the higher R_s of a-GST polishing can be gained after CMP using both pads and the high R_s is beneficial to lower the reset current for the PCM cells. In order to find the root cause of the different RR of a-GST polishing with different pads,the surface morphology and characteristics of both new and used pads are analyzed,it shows that the AT pad has smaller porosity size and more pore counts than that of the REG pad,and thus the AT pad can transport more fresh slurry to the reaction interface between the pad and a-GST,which results in the high RR of a-GST due to enhanced chemical reaction.     

Effect of external stress on phase diagrams and dielectric properties of epitaxial ferroelectric thin films grown on orthorhombic substrates

1 Introduction Ferroelectric thin films have been widely investigated in recent years. Not only the ferroelectric, dielectric, and piezoelectric properties were found to be promising for microelectric and micromechanical applications[1], but also the phy…     

Ge_(15)Ga_(10)Te_(75)薄膜的磁控溅射制备及性能的可控研究

采用磁控溅射法制备了Ge_(15)Ga_(10)Te_(75)薄膜,研究溅射工艺对薄膜结构与性能的影响,并分析了在不同热处理温度(200~280℃)退火后薄膜光学特性的变化。通过扫描电子显微镜、X射线衍射仪、显微拉曼光谱仪、分光光度计等测试手段对热处理前后薄膜样品的微观结构和光学特性进行了表征,结果表明,3次不同工艺下制备的沉积态薄膜组分与靶材偏差较小,且均是非晶态。沉积态薄膜的短波截止波长均在1μm左右;当退火温度(Ta)大于薄膜的玻璃转化温度(Tg)时,薄膜的光学带隙(Egopt)随着退火温度的增加而逐渐减小,沉积态薄膜的光学带隙分别为1.05,1.06和1.07eV,而在280℃退火后薄膜光学带隙分别降至0.38,0.42和0.45eV,以上3次实验结果表明,不同工艺下制备的Ge_(15)Ga_(10)Te_(75)薄膜组分均匀可控,热学和光学参数较一致。