Title :
Metal migration into polysilicon emitter after very high current stress
Author :
Tang, Denny D. ; Wong, Catherine ; McFarland, P.A.
Author_Institution :
IBM Almaden Res. Center, San Jose, CA, USA
fDate :
5/1/1992 12:00:00 AM
Abstract :
TEM analyses show metal migration into the polysilicon emitter of a bipolar transistor after high current stress. At the edges of the polysilicon emitter where the current density was expected to be the highest, a metal filament was seen penetrating into the edge of the polysilicon emitter after stressing at a current density of 16.3 mA/ mu m/sup 2/ for 1.68*10/sup 5/ s at 90 degrees C. The metal penetration into polysilicon offers a possible cause for an electrical measurement reported by D.D. Tang et al. (1990), in which a slight lowering of the emitter contact resistance occurs after the same stress.<>
Keywords :
bipolar transistors; current density; electromigration; elemental semiconductors; silicon; transmission electron microscope examination of materials; TEM analyses; bipolar transistor; contact resistance; current density; high current stress; metal filament; metal migration; metal penetration; polycrystalline Si; polysilicon emitter; Acceleration; Bipolar transistors; Contact resistance; Counting circuits; Current density; Electric variables measurement; Electrical resistance measurement; Grain boundaries; Stress measurement; Temperature;
Journal_Title :
Electron Device Letters, IEEE
