Liquid-phase epitaxial layers of Ga1-xAlxAs with various Al contents were studied by using a diffusion source which contained GaS and As in the mass ratio of 2:1. The diffusion of S was carried out in a sealed quartz ampoule at 820C, and in ambient As at a vapour pressure of 1atm. The value of x ranged from 0 to 0.3 (table 11). The diffusion data for GaAs and Ga0.7Al0.3As could be described by:

D (cm2/s) = 1.6 x 109 exp[-4.7(eV)/kT]

and

D (cm2/s) = 1.9 exp[-2.5(eV)/kT]

respectively. Smooth S diffusion was observed, which did not cause any surface damage.

Sulfur Diffusion into Ga1-xAlxAs with Various Al Contents H.Nishi, Y.Horikoshi, H.Ito: Journal of Applied Physics, 1998, 84[10], 5811-3

 

Table 11

Diffusivity of S in Ga1-xAlxAs at 820C

 

x

D (cm2/s)

0

3.5 x 10-13

0.08

2.0 x 10-12

0.2

3.5 x 10-12

0.3

5.5 x 10-12