Diffusion control of dopant from heavily Se doped n type GaAs layers grownby molecular layer epitaxy

Properties of GaAs grown by molecular layer epitaxy are strongly influenced by surface stoichiometry during growth, In molecular layer epitaxy, Se is introduced for the heavily doped n(+ +) layers for device applications. In such layers, Se exists as an interstitial atom and behaves as a diffusion s ource. In the growth process, the diffusion of doped Se into GaAs is affect ed by the supply pressure of AsH3; a higher amount of AsH3 supplied during the growth of the undoped layer in an n(+ +)-i structure reduces the diffus ion of Se. A lower amount of AsH3 supplied during the growth of the n(+ +) layer reduces the diffusion of Se from the n(+ +) layer to the i layer. The stoichiometry in i and n(+ +) layers affects the diffusion of interstitial Se in different manners.