Title :
Kinetics of copper drift in PECVD dielectrics
Author :
Loke, Alvin L S ; Ryu, Changsup ; Yue, C. Patrick ; Cho, James S H ; Wong, S. Simon
Author_Institution :
Center for Integrated Syst., Stanford Univ., CA, USA
Abstract :
We quantified the drift of Cu ions into various PECVD dielectrics by measuring shifts in capacitance-voltage behavior after subjecting Cu-gate MOS capacitors to bias-temperature stress. At a field of 1.0 MV/cm and temperature of 100/spl deg/C, Cu ions drift readily into PECVD oxide with a projected accumulation of 2.7/spl times/10/sup 13/ ions/cm/sup 2/ after 10 years. However, in PECVD oxynitride, the projected accumulation under the same conditions is only 2.3/spl times/10/sup 10/ ions/cm/sup 2/. These findings demonstrate the necessity of integrating drift barriers, such as PECVD oxynitride layers, in Cu interconnection systems to ensure threshold stability of parasitic field n-MOS devices.
Keywords :
CVD coatings; MOS capacitors; copper; dielectric thin films; diffusion; 100 C; Cu; Cu-gate MOS capacitor; PECVD dielectric; bias-temperature stress; capacitance-voltage characteristics; copper ion drift kinetics; drift barrier; interconnection; oxide layer; oxynitride layer; parasitic field n-MOS device; threshold stability; Capacitance measurement; Capacitance-voltage characteristics; Copper; Dielectric measurements; Dielectric substrates; Kinetic theory; MOS capacitors; Plasma temperature; Temperature distribution; Testing;
Journal_Title :
Electron Device Letters, IEEE
