The liquidus surfaces of ternary systems involving compound semiconductors: II. Calculation of the liquidus isotherms an
- PDF / 887,591 Bytes
- 6 Pages / 569 x 814 pts Page_size
- 8 Downloads / 218 Views
The previously derived liquidus equation for an AB compound (GaAs or GaP) incorporating a dilute solute (zinc) in equilibrium with a ternary regular melt was applied to the available liquidus data in the Ga-As and Ga-As-Zn and in the Ga-P and Ga-P-Zn systems. The ternary interchange energies for both systems were computed by the method of multidimensionalleastsquares. Utilizing these interchange energies, the liquidus isotherms in the Ga-As-Zn and Ga-P-Zn systems were calculated over a wide temperature range from the nonlinear liquidus equation by a numerical method. By a combination of the ternary regular activity coefficients with the vapor pressures of the pure components and the liquidus isotherms, the component partial pressures alongthe liquidus isotherms were determined. The ternary liquidus and partial pressure isotherms are in good agreement with the experimental data of Panish, Koster and Ulrich, and Shih et al. It is further shown that in the binary limit, the results of these calculations are also in accord with liquidus and partial pressure measurements for the Ga-As and Ga-P systems. Z I N C is one of the m o s t i m p o r t a n t p - t y p e dopants in G a P and G a A s . In p a r t i c u l a r , z i n c is a c o m m o n l y u s e d i m p u r i t y in G a P e l e c t r o l u m i n e s c e n t r e d ' and g r e e n light emitting diodes. 2 Moreover, GaAs 3 reverse biased p-n junction microwave oscillators utilize zinc as a dopant. Since z i n c in t h e s e c r y s t a l s is v e r y often i n c o r p o r a t e d by l i q u i d - p h a s e e p i t a x i a l g r o w t h , s o l u tion g r o w t h , o r d i f f u s i o n , the d e s i g n and a n a l y s i s of s u c h e x p e r i m e n t s r e q u i r e a d e t a i l e d k n o w l e d g e of the G a - A s - Z n and G a - P - Z n l i q u i d u s i s o t h e r m s and c o m ponent partial pressures. In the p r e c e d i n g p a p e r 4 ( h e n c e f o r t h r e f e r r e d to as I) a l i q u i d u s e q u a t i o n ( I - E q . [11]) was d e r i v e d f o r a b i n a r y s o l i d c o m p o u n d , s u c h as G a P , i n c o r p o r a t i n g a s m a l l a m o u n t of i m p u r i t y , in e q u i l i b r i u m with a reg-ul a r t e r n a r y liquid s o l u t i o n . T h e m a i n o b j e c t i v e of the p r e s e n t w o r k is to a n a l y z e the t e r n a r y l i q u i d u s d a t a f o r the G a - A s - Z n and G a - P - Z n s y s t e m s in c o m b i n a tion with the b i n a r y G a - A s and G a - P d a t a by m e a n s of t h i s l i q u i d u s e q u a t i o n . T h i s a n a l y s i s p e r m i t s the c a l c u l a t i o n of the t e r n a r y l i q u i d u s i s o t h e r m s and of the Zn, As2, As4, P2 and P4 p a r t i a l p r e s s u r e s a l o n g t h e s e i s o t h e r m s o v e r a wide t e m p e r a t u r e r a n g e . It is f u r t h e r shown that the p a r t i a l p r e s s u r e s and l i q u i d u s i s o t h e r m s a r e in good a g r e e m e n t with the a v a i l a b l e t e r n a r y and b i n a r y data. ANALYSIS O F T H E
Data Loading...
