Dislocation sources in silicon
- PDF / 4,188,493 Bytes
- 9 Pages / 612 x 792 pts (letter) Page_size
- 79 Downloads / 213 Views
T
H
E
i m p e t u s for t h i s w o r k was p r o v i d e d by the o b s e r v a t i o n of d i s c r e t e d i s l o c a t i o n g e n e r a t i n g s o u r c e s in s i l i c o n w a f e r s s u b j e c t e d to oxidation and b o r o n diffusion followed by high t e m p e r a t u r e a n n e a l i n g t r e a t m e n t s . Z It w a s o b s e r v e d that o x i d a t i o n i n d u c e d s t a c k i n g faults functioned a s s o u r c e s for d i s l o c a t i o n g e n e r a t i o n d u r i n g a n n e a l i n g , the g e n e r a t i o n o c c u r r i n g in a m a n n e r a n a l o gous to the B a r d e e n - H e r r i n g 2 m e c h a n i s m of d i s l o c a t i o n g e n e r a t i o n giving r i s e to a m u l t i p l e s y s t e m of c o n c e n t r i c d i s l o c a t i o n l o o p s . The p r e s e n t p a p e r is a r e p o r t of a m o r e d e t a i l e d e x a m i n a t i o n of t h i s phenomenon. T h a t oxidation of s i l i c o n f r e q u e n t l y r e s u l t s in the g e n e r a t i o n of shallow s t a c k i n g faults in the s u r f a c e is w e l l known. 3-7 B o o k e r and T u n s t a l l 6 and J o s h i 7 have i d e n t i f i e d the e x t r i n s i c n a t u r e of t h e s e f a u l t s u s i n g t r a n s m i s s i o n e l e c t r o n m i c r o s c o p y and B o o k e r and T u n s t a l l have shown that t h e s e f a u l t s a r e bounded by F r a n k p a r t i a l d i s l o c a t i o n s . The m e c h a n i s m of i n i t i a t i o n and g r o w t h of t h e s e f a u l t s has b e e n s u g g e s t e d to be s i m i l a r to that p r o p o s e d by S i l c o c k and T u n s t a l l ~ f o r the n u c l e a t i o n and g r o w t h of niobium c a r b i d e p r e c i p i t a t e s in s t a i n l e s s s t e e l . T h i s m e c h a n i s m i n v o l v e s the f o r m a t i o n of a p r e c i p i t a t e in the p a r e n t m a t r i x , the g e n e r a t i o n of a s t a c k i n g fault and e s t a b l i s h m e n t of a none q u i l i b r i u m c o n c e n t r a t i o n of point d e f e c t s and hence g r o w t h of the fault by the c l i m b of the F r a n k p a r t i a l s bounding the fault in o r d e r to r e e s t a b l i s h point d e f e c t e q u i l i b r i u m . The s e c o n d p h a s e r e s p o n s i b l e for the g e n e r a t i o n and m o t i o n of F r a n k p a r t i a l s in s i l i c o n has b e e n s u g g e s t e d to be an oxide of s i l i c o n such as t r i d y m i t e o r c r i s t o b a l i t e . 6 Stacking f a u l t s d e c o r a t e d by a s e c o n d p h a s e have b e e n o b s e r v e d in s i l i c o n 9 lending c r e d i b i l i t y to t h i s m e c h a n i s m of fault growth. An o p p o s i n g point of view has b e e n a d v a n c e d by J a c c o d i n e and D r u m 1~ and S a n d e r s and Dobson 11 which m a i n t a i n s that p r e c i p i t a t i o n i s not a p r e r e q u i s i t e for fault growth and that growth t a k e s p l a c e owing to the e m i s s i o n of
K. V. RAVI is Manager, Metallurgical Technology Section, Central Research Laborat
Data Loading...
