Formation and nonvolatile memory characteristics of W nanocrystals by in-situ steam generation oxidation

• Published in: Thin solid films Vol. 519; no. 5; pp. 1677 - 1680
• Main Authors: Chen, Shih-Cheng, Chang, Ting-Chang, Hsieh, Chieh-Ming, Li, Hung-Wei, Sze, S.M., Nien, Wen-Ping, Chan, Chia-Wei, Yeh(Huang), Fon-Shan, Tai, Ya-Hsiang
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 30-12-2010; Elsevier
• Subjects: Charge; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Composition and phase identification; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Data storage; Durability; Exact sciences and technology; In-situ stem generation; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nanocrystals; Nanoscale materials and structures: fabrication and characterization; Nonvolatile memory; Other topics in nanoscale materials and structures; Oxidation; Physics; Steam generation; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Thin films; Trapping; Tungsten; Nonvolatile memory; Nanocrystals; Tungsten; In-situ stem generation; Charge storage; Memory devices; Thin films; CVD; Electrical measurement; Trapping; Transmission electron microscopy; Non volatile memory; Silicon oxides; Low pressure; Steam; Chemical composition; Oxidation; Silicon; Reliability; Scanning transmission electron microscopy; Microstructure; Memory effect; Nanostructured materials; Nanocrystal
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2010.08.167

The authors provide the formation and memory effects of W nanocrystals nonvolatile memory in this study. The charge trapping layer of stacked a-Si and WSi
2 was deposited by low pressure chemical vapor deposition (LPCVD) and was oxidized by in-situ steam generation system to form uniform W nanocrystals embedded in SiO
2. Transmission electron microscopy analyses revealed the microstructure in the thin film and X-ray photon-emission spectra indicated the variation of chemical composition under different oxidizing conditions. Electrical measurement analyses showed the different charge storage effects because the different oxidizing conditions influence composition of trapping layer and surrounding oxide quality. Moreover, the data retention and endurance characteristics of the formed W nanocrystal memory devices were compared and studied. The results show that the reliability of the structure with 2% hydrogen and 98% oxygen at 950
°C oxidizing condition has the best performance among the samples.