成果報告書詳細
管理番号20110000001268
タイトル*平成22年度中間年報 ナノテク・先端部材実用化研究開発/水素拡散を制御した高信頼性絶縁膜の開発とフラッシュメモリーへの応用
公開日2011/8/30
報告書年度2010 - 2010
委託先名独立行政法人物質・材料研究機構 ルネサスエレクトロニクス株式会社 独立行政法人産業技術総合研究所 国立大学法人東京大学 株式会社日立国際電気
プロジェクト番号P05023
部署名電子・材料・ナノテクノロジー部
和文要約和文要約等以下本編抜粋:~ 担 当 ~
(1)独立行政法人物質・材料研究機・br>(2)ルネサスエレクトロニクス株式会社、株式会社日立国際電気
(3)独立行政法人産業技術総合研究所
(4)国立大学法人東京大学
(1)独立行政法人物質・材料研究機構 担当部分
1.研究開発の内容及び成果等 本研究では、次世代フラッシュメモリーを高密度化し絶縁膜の信頼性を向上するために、膜中にナノレベルの水素貯蔵層を埋め込み、酸化物/Si界面の劣化を抑制するための新材料の開発をコンビナトリアル手法で探索することを目的としている。そのために、独立行政法人物質・材料研究機構、ルネサスエレクトロニクス株式会社、独立行政法人産業技術総合研究所、東京大学、株式会社日立国際電気がそれぞれ協力し、目標を実現するための研究開発項目を実施している。その中で、独立行政法人 物質・材料研究機構では平成22 年~平成23年3月までに、
(1)~2「現行フラッシュメモリーの水素貯蔵層の組成と構造の解明」の理論解析
(2)「コンビナトリアル手法による水素貯蔵層超薄膜の探索と機構解明」
(3)~1「プレーナー型電極/水素貯蔵層/SiN/SiO2/Siの作製と特性評価」
(4)~3「トンネル領域形状が及ぼすトンネル絶縁膜信頼性への影響調査」
を行った。
英文要約In this research project, to achieve a highly reliable insulating oxide for future flash memory, we develop a hydrogen storage layer at the gate and nitride layer to improve durability of the insulating layer.
The first principle calculation predicted that Si2N2O could keep hydrogen stably inside the structure. The Si2N2O has Si-N layered structures connected by Si-O-Si bonds. Taking some oxygen atoms in this Si2N20, dangling bonds were formed in Si atoms. Subsequently facing Si atoms came close to make bonding using dangling bonds. Here small cage structures were form between Si-N layers . When hydrogen atoms came into these layers, the hydrogen atoms were trapped the holes as H2 molecules.
It was also proved that the combined nitridation process is able to make remarkable improvement on the CVD dielectric lifetime (Qbd). During the oxide nitrided by N2O, the new nitridation method showed the improvement the oxide quality due to the formation of N-rich H-storage oxynitride layer at the interface region between poly-Si/oxynitride. We suggested that the N-rich H-storage layer was promising for enhancing the reliability of the tunnel dielectrics.
  To find more effective hydrogen reservoir, Al2O3 and SiAlON were characterized by NRA. When the Al2O3 / SiAlON / Si3N4 / SiO2 / Si(100) stack structure was examined, the hydrogen quantity was furthermore enhanced and the hydrogen diffusion was considerably suppressed. These results strongly suggest that the Al2O3 / SiAlON / Si3N4 stack is a suitable structure for the flash memory.
  Also in this work, we have developed three kinds of key processes for fabrication of the flash memories with three-dimensional (3D) tunnel areas and low programming-erasing voltage. First, we have developed FinFET fabrication processes using orientation dependent wet etching. Second, we investigated the rapid thermal annealing (RTA) temperature dependence of the electrical characteristics for PVD-TiN gate FinFETs, and determined the optimal RTA temperature. Third, we have developed and evaluated the electrical characteristics of the flash type MOS capacitors with 3D tunnel areas fabricated by using orientation dependent wet etching.
 In the flash type MOS capacitor fabrication, we used (100)-oriented SOI wafers as a stating material, and the 3D tunnel areas with a triangle cross-section were fabricated by using electron beam lithography and orientation-dependent wet etching technique as mentioned before. From the obtained results,it was experimentally confirmed that 3D tunnel area is very effective to reduce charge injection voltage.
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