Nano-scale gap filling and mechanism of deposit-etch-deposit process for phase-change material

Nano-scale gap filling and mechanism of deposit-etch-deposit process for phase-change material

Ren Wan-Chun;Liu Bo;Song Zhi-Tang;Xiang Yang-Hui;Wang Zong-Tao;Zhang Bei-Chao;Feng Song-Lin

【期刊名称】《中国物理：英文版》 【年(卷),期】2012(021)011

【摘要】Ge2Sb2Te5 gap filling is one of the key processes for phase-change random access memory manufacture.Physical vapor deposition is the mainstream method of Ge2Sb2Te5 film deposition due to its advantages

of

film

quality,purity,and

accurate

composition

control.However,the conventional physical vapor deposition process cannot meet the gapfilling requirement with the critical device dimension scaling down to 90 nm or below.In this study,we find that the deposit-etch-deposit process shows better gap-filling capability and scalability than the single-step deposition process,especially at the nano-scale critical dimension.The gap-filling mechanism of the deposit-etch-deposit process was briefly discussed.We also find that re-deposition of phase-change material from via the sidewall to via the bottom by argon ion bombardment during the etch step was a key ingredient for the final good gap filling.We achieve void-free gap filling of phase-change material on the 45-nm via the two-cycle deposit-etch-deposit process.We gain a rather comprehensive insight into the