Growth of germanium films on glass

282

WORLD

ABSTRACTS

ON

MICROELECTRONICS

m a d e in b o t h areas, t h e m a j o r i m p r o v e m e n t s b e i n g increased quality and reliability of thick-film electronic components

Propagating m a g n e t i c w a v e s in thick-films. A c o m p l e m e n t a r y technology to surface w a v e acoustics. J H COLLINS a n d F. A PIZZARELLO Int ff Electron 34, N o 3 (1973), p 319 A n e w f o r m o f r m c r o wave integrated circuit s e e m s reahzable u t l h z l n g p r o p a g a t t n g m a g n e t i c waves in epltaxlal films of y t t r i u m iron g a r n e t ( Y I G ) T h e t e c h n o l o g y is c o m p l e m e n t a r y to t h a t of surface acoustic w a v e s w i t h t h e a d v a n t a g e of operation u p to 10 G H z B o t h dispersive a n d n o n dispersive properties m a y be realized with t h e m a g n e t i c waves by u s i n g suitably coded, spatially periodic, transd u c e r s T h e c o n f i n e m e n t of energy to t h i n m a g n e t i c films p e r m i t s t h e fabrication of t a p p e d delay h n e s A m a t r i x array of t r a n s d u c e r s , in c o n j u n c t i o n w i t h t h e a m s o t r o p i c n a t u r e of m a g n e t i c wave propagation, has p e r m i t t e d t h e fabrmatlon of electromcally steerable delay lines T h e spatial profiles of these m a g n e t i c b e a m s have b e e n m e a s u r e d by surface p r o b i n g t e c h n i q u e s Selective e t c h i n g of t h e Y I G s a m p l e s allows m a g n e t i c w a v e g u l d e s a n d directional couplers to be integrated with t h e o t h e r devices for signal processing p u r p o s e s

Size-effect parameters for thin-films of the alum i n i u m group metals. C REALE Sohd S t Commun 12 (1973), p 421 M e a s u r e m e n t s were m a d e of the s h e e t resistivity a n d Hall voltage of ~ a c u u m - d e p o s l t e d polyc r y s t a l h n e a l u m m l u m , gallium, i n d i u m a n d t h a l l i u m films 500-5000 A thick, cooled to 4 2 ° K T h e results fit a l o w - t e m p e r a t u r e f o r m of t h e S o n d h e l m e r size-effect relations, a n d m a y t h e n be u s e d to d e t e r m i n e t h e electron transport parameters

Hybrid thick-film circuits. G BROOKE a n d W E B BALDWIN W, reless World, M a r c h (1973), p 121 It can be said here that t h e thick-film t e c h n i q u e incurs very low t o o h n g costs relative to m o n o l i t h i c c~rcults and h e n c e even s a m p l e q u a n t m e s are n o t e x p e n s i v e , in q u a n t i t y t h e price p e r u n i t IS even lower a n d wdl generally level off at a b o u t t h e 2000 m a r k O t h e r positive reasons for c h o o s i n g thick-film circuits are (a) t h e y cater for a wide range of C a n d R a n d h i g h e r voltages, (b) t h e y are able to dissipate h i g h powers w i t h o u t d a m a g i n g t h e p e r f o r m a n c e of t h e l o w e r - p o w e r parts of t h e circuit, (c) t h e y are particularly suitable for analogue circuits w h e r e t h e range of m o n o l i t h i c integrated circuits does n o t m a t c h u p to t h e d e m a n d s of t h e great diversity of a p p h e a t l o n s , (d) t h e y can he d e s i g n e d to fit exactly t h e c u s t o m e r ' s circuit w i t h o u t t h e necessity of trying to a d a p t s t a n d a r d circuits to p r o d u c e t h e desired p e r f o r m ance

T h e r m a l considerations in the design of hybrid microelectronic packages. R C BUCHANAN and M D REEBER Sohd S t Technol, F e b r u a r y (1973), p 39 T h e r m a l considerations arise in the design of h y b r i d Imcroelectromc packages because of t h e need to control t h e e m i t t e r - b a s e j u n c t i o n t e m p e r a t u r e of t h e

AND

RELIABILITY

s e r m c o n d u e t o r devices for o p t i m u m p e r f o r m a n c e T h e drive to i m p r o v e p e r f o r m a n c e specifications leads to t h e m i n i a t u r i z a t i o n of c o m p o n e n t s w i t h increased p o w e r densities a n d r e d u c e d j u n c t i o n t e m p e r a t u r e limits T h u s , t h e control of heat dissipation b e c o m e s a critical design p a r a m e t e r F o r a h y b r i d package, t h e r m a l energy is dissipated f r o m t h e j u n c t i o n source t h r o u g h an internal t h e r m a l resistance ( j u n c t i o n to package surface) a n d a n external resistance (package surface to ambient), t h e latter d e p e n d i n g mainly on heat transfer conditions T h e internal resistance d e p e n d s on material a n d geometrical p a r a m e t e r s i n c l u d i n g j u n c t i o n a n d chip size, b o n d i n g a n d s u b s t r a t e m a t e r i a l s - - t h e effects of w h i c h are d i s c u s s e d relating to heat flow a n d packaging d e n s i t y

The classification and quality control of thln-films by the recognition of X-ray diffraction lines. S KAWARAI, R

KOIKE, M

SHINTANI a n d N

FURUYA

Trans. Inst Electron & Commun EngrsJapan 56, N o 1, J a n u a r y (1973), p 23 T h i s p a p e r discusses a m e t h o d w h e r e b y t h e classification a n d q u a h t v control of t a n t a l u m t h m - f i l m s can be carried o u t w i t h o u t t r o u b l e s o m e electrical examinations, by u t i h z l n g t h e F o u r i e r c o m p o n e n t s a n d t h e expected values of t h e X - r a y diffraction h n e s of t h e films (as a p a t t e r n recognition m e t h o d )

Thick-film switches perform semiconductor functions. F K PATTERSON, S C THAYER, L C HOFF~AN and R M ROSENBERG Electron Engng, F e b r u a r y (1973), p 63 A n e w class of thick-film compositions ( T y o x Is,) provides p r i n t e d a n d fired e l e m e n t s that exhibit t h r e s h hold switching characteristics T h e y can p e r f o r m s o m e of t h e f u n c t i o n s of s e m i c o n d u c t o r devices a n d of m e c h a n i c a l or electromechamcal switches in m a n y applications, with cost savings i n h e r e n t b o t h m on-line processibihty w i t h passive, thick-film c o m p o n e n t s , a n d absence of separate m t e r c o n n e c t l o n steps

Growth of g e r m a n i u m films on glass. R K A~ORA Int ff Electron 34, N o 2 (1973), p 193 Crystalline g e r m a n i u m films were g r o w n by v a c u u m evaporation on heated c o m i n g glass substrates I n t r i n s i c g e r m a n i u m (99 999 per cent a n d of 30 ~ - c m resistivity) was evaporated f r o m a r e s i s t a n c e - h e a t e d t u n g s t e n conical basket pasted w i t h a paste of s o d i u m slhcate a n d a l u m i n a on to cleaned microscope glass slides w i t h t h e help of a conventlonal v a c u u m s y s t e m at p r e s s u r e b e t w e e n 10 -5 and 10 -4 t o r t T h e electrical conductivity of t h e films was m e a s u r e d in v a c u u m at t e m p e r a t u r e s v a r y i n g b e t w e e n 77 a n d 4 0 0 ° K T h e island radius of t h e film is calculated u s i n g t h e Frenkel m o d e l a n d t h e grain size was f o u n d to Increase with thickness P a r t i a l d i s o r d e r i n evaporated a l u m i n i u m f i l m s . O D HUNDERI Sohd S t Commun. 12, No. 3 (1973), p 237 A simple m o d e l w h e r e it was a s s u m e d t h a t t h e material n e a r t h e grain b o u n d a r i e s constitute a disordered phase, h a s b e e n u s e d to explain t h e influence of deposition s u b s t r a t e t e m p e r a t u r e on t h e optical p r o pertles of a l u m l m u m