ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Representative length scale of ULSI (Ultra Large Scale Integration) cells is going to be ata nano-meter order, and the atomic level defects, such as uneven oxide films or dislocationaccumulation are becoming more and more important. Among these defects, dislocationaccumulation is known to be caused by thermo-plastic deformation in silicon during the processesof device fabrication. In this study, we analyse such thermal stress, plastic slip deformation andaccumulation of dislocations in STI (Shallow Trench Isolation) type ULSI devices when thetemperature drops from the initial at 1000 ℃ to room temperature. For the analysis, we use acrystal plasticity analysis code CLP, assuming that lattice friction stress for the movement ofdislocations is proportional to the hardness of silicon, which is known to have strong dependencyon temperature. The results show that dislocations are generated between the temperature rangefrom 880 to 800 ℃, and its maximum density is highly dependent on the lattice friction stress inthe temperature range above 800 ℃. For example, the difference of 16 MPa in the lattice frictionstress at 1000 ℃ caused increase in dislocation density more than ten times. It is concluded thatcontrol of lattice friction stress at high temperatures is one of the most promising way for thesuppression of dislocation accumulation
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/54/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.340-341.199.pdf
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