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Epitaxy and the early stages of electrocrystallization I: The electrodeposition of nickel and copper on (001) Ag and (001) Cu single-crystal substrates
Surface Technology, 12 (1981) 13
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E P I T A X Y A N D THE E A R L Y S T A G E S OF ELECTROCRYSTALLIZATION I: THE E L E C T R O D E P O S I T I O N OF NICKEL A N D C O P P E R ON (001) Ag A N D (001) Cu S I N G L E - C R Y S T A L S U B S T R A T E S *
J. P. G. FARR, A. J. S. McNEIL AND C. A. LOONG Department of Industrial Metallurgy, The University, Birmingham B15 2TT (Gt. Britain)
O b s e r v a t i o n of the e a r l y s t a g e s of e l e c t r o c r y s t a l l i z a t i o n of m e t a l s o n t o foreign s u b s t r a t e s is basic to the c o m p r e h e n s i o n of s u b s e q u e n t g r o w t h a n d to c o n t r o l of e l e c t r o p l a t i n g a p p l i c a t i o n s in e l e c t r o n i c device m a n u f a c t u r e . In the t w o p a r t s of this c o n t r i b u t i o n e x a m p l e s are g i v e n c o n t r a s t i n g m o d e s of g r o w t h in t h e f o r m a t i o n of the first 1000 A t h i c k n e s s of e l e c t r o d e p o s i t s . First, the p r e p a r a t i o n of s u i t a b l e s u b s t r a t e s a n d t h e i r c h a r a c t e r i s t i c s a r e s u m m a r i z e d . D e p o s i t s g r o w n on t h e s e s u b s t r a t e s w e r e e x a m i n e d by v a r i o u s t e c h n i q u e s of e l e c t r o n m i c r o s c o p y w h i c h a r e d e s c r i b e d briefly. D e p o s i t s of c o p p e r on s i l v e r s u b s t r a t e s w e r e n o n - c o n t i n u o u s and c o n c e n t r a t e d o n defects. H o w e v e r , n i c k e l films on this s u b s t r a t e w e r e c o n t i n u o u s a t a v e r y e a r l y stage. Good e p i t a x y o c c u r r e d in b o t h cases. F o r copper, m e r g i n g nuclei allowed the f o r m a t i o n of misfit d i s l o c a t i o n s a n d r e l a x a t i o n of the g r o w i n g lattice. By c o n t r a s t , n i c k e l r e t a i n e d l a t t i c e s t r a i n to g r e a t e r t h i c k n e s s e s . This effect w a s o b s e r v e d in c o n s i d e r a b l e detail on c o p p e r s u b s t r a t e s , w h e r e a new g r o w t h d i s l o c a t i o n was m a n i f e s t before the classical misfit d i s l o c a t i o n s were p r o p a g a t e d . A r e p l i c a e l e c t r o n m i c r o s c o p e s t u d y of t h e e l e c t r o d e p o s i t i o n of c o p p e r o n t o a c o p p e r single c r y s t a l n e a r (100) s h o w e d t h a t , e v e n u n d e r c o n d i t i o n s w h e r e " b u n c h i n g " of g r o w t h l a y e r s would be e x p e c t e d to be the p r e d o m i n a n t f e a t u r e , n u c l e a t i o n was a m a r k e d f e a t u r e of t h e e a r l y s t a g e s of growth. T h e g r o w t h of initial nuclei is discussed a n d s o m e c o m m e n t s a r e offered on the effectiveness of s u b s t r a t e defects in the n u c l e a t i o n processes.
* Abstract of a paper presented at the Conference on Fundamentals of Electroplating and Metal Finishing, Loughborough, September 22 - 24, 1980. 0376-4883/81/0000-0000/$02.50
~C:Elsevier Sequoia/Printed in The Netherlands
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E P I T A X Y A N D THE E A R L Y S T A G E S OF ELECTROCRYSTALLIZATION I: THE E L E C T R O D E P O S I T I O N OF NICKEL A N D C O P P E R ON (001) Ag A N D (001) Cu S I N G L E - C R Y S T A L S U B S T R A T E S *
J. P. G. FARR, A. J. S. McNEIL AND C. A. LOONG Department of Industrial Metallurgy, The University, Birmingham B15 2TT (Gt. Britain)
O b s e r v a t i o n of the e a r l y s t a g e s of e l e c t r o c r y s t a l l i z a t i o n of m e t a l s o n t o foreign s u b s t r a t e s is basic to the c o m p r e h e n s i o n of s u b s e q u e n t g r o w t h a n d to c o n t r o l of e l e c t r o p l a t i n g a p p l i c a t i o n s in e l e c t r o n i c device m a n u f a c t u r e . In the t w o p a r t s of this c o n t r i b u t i o n e x a m p l e s are g i v e n c o n t r a s t i n g m o d e s of g r o w t h in t h e f o r m a t i o n of the first 1000 A t h i c k n e s s of e l e c t r o d e p o s i t s . First, the p r e p a r a t i o n of s u i t a b l e s u b s t r a t e s a n d t h e i r c h a r a c t e r i s t i c s a r e s u m m a r i z e d . D e p o s i t s g r o w n on t h e s e s u b s t r a t e s w e r e e x a m i n e d by v a r i o u s t e c h n i q u e s of e l e c t r o n m i c r o s c o p y w h i c h a r e d e s c r i b e d briefly. D e p o s i t s of c o p p e r on s i l v e r s u b s t r a t e s w e r e n o n - c o n t i n u o u s and c o n c e n t r a t e d o n defects. H o w e v e r , n i c k e l films on this s u b s t r a t e w e r e c o n t i n u o u s a t a v e r y e a r l y stage. Good e p i t a x y o c c u r r e d in b o t h cases. F o r copper, m e r g i n g nuclei allowed the f o r m a t i o n of misfit d i s l o c a t i o n s a n d r e l a x a t i o n of the g r o w i n g lattice. By c o n t r a s t , n i c k e l r e t a i n e d l a t t i c e s t r a i n to g r e a t e r t h i c k n e s s e s . This effect w a s o b s e r v e d in c o n s i d e r a b l e detail on c o p p e r s u b s t r a t e s , w h e r e a new g r o w t h d i s l o c a t i o n was m a n i f e s t before the classical misfit d i s l o c a t i o n s were p r o p a g a t e d . A r e p l i c a e l e c t r o n m i c r o s c o p e s t u d y of t h e e l e c t r o d e p o s i t i o n of c o p p e r o n t o a c o p p e r single c r y s t a l n e a r (100) s h o w e d t h a t , e v e n u n d e r c o n d i t i o n s w h e r e " b u n c h i n g " of g r o w t h l a y e r s would be e x p e c t e d to be the p r e d o m i n a n t f e a t u r e , n u c l e a t i o n was a m a r k e d f e a t u r e of t h e e a r l y s t a g e s of growth. T h e g r o w t h of initial nuclei is discussed a n d s o m e c o m m e n t s a r e offered on the effectiveness of s u b s t r a t e defects in the n u c l e a t i o n processes.
* Abstract of a paper presented at the Conference on Fundamentals of Electroplating and Metal Finishing, Loughborough, September 22 - 24, 1980. 0376-4883/81/0000-0000/$02.50
~C:Elsevier Sequoia/Printed in The Netherlands