Mechanical Stress Analysis of Trench Isolation Using a Two-Dimensional Simulation

Satoshi MATSUDA  Nobuyuki ITOH  Chihiro YOSHINO  Yoshiroh TSUBOI  Yasuhiro KATSUMATA  Hiroshi IWAI  

IEICE TRANSACTIONS on Electronics   Vol.E77-C   No.2   pp.124-128
Publication Date: 1994/02/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on 1993 VLSI Process and Device Modeling Workshop (VPAD 93))
Category: Process Simulation
trench isolation,  shallow trench,  deep trench,  high-speed bipolar LSIs,  leakage current,  mechanical stress,  

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Junction leakage current of trench isolation devices is strongly influenced by trench configuration. The origin of the leakage current is the mechanical stress that is generated by the differential thermal expansion between the Si substrate and the SiO2 filled isolation trench during the isolation forming process. A two-dimensional mechanical stress simulation was used to analyze trench-isolated devices. The simulated distribution and magnitude of stress were found to agree with Raman spectroscopic measurements of actual devices. The stress in the deeper regions between deep trenches is likely to increase greatly as the size of devices diminishes, so it is important to reduce this stress and thus suppress junction leakage current.