HIGH CONCENTRATION ARSENIC DIFFUSION IN SILICON FROM A DOPED OXIDE SOURCE.

The properties of As-doped SiO//2 and As-doped Ge/SiO//2 diffusion sources as a function of the O//2 concentration in a horizontal, open-tube deposition chamber are examined. The effect of the Ge doping in the oxide is to enhance the etch rate and to reduce As//2O//3 incorporated during the oxidation of AsH//3. The elemental As thus formed diffuses more rapidly than As//2O//3 in the oxide, thus enhancing the transport of As across the Si-oxide interface. A prediffusion H//2 anneal of the oxide is shown to produce a similar effect. Singly diffused As profiles in Si are shown to be described by the solutions to the diffusion equation with a concentration-dependent diffusion coefficient. However, the preanneal in H//2 is shown to cause the subsequently diffused As to have an anomalous electrical profile.

Duke Scholars

Author Richard B. Fair Electrical and Computer Engineering