Enhancement of Si hole mobility in coupled deltahyphen;doped wells

摘要

When two or more highly doped, thin (deltahyphen;doped) layers are placed in close proximity to one another it is found that an enhancement of the hole mobility occurs over that of a single delta (dgr;) layer as well as that of the Si bulk case. Hall mobilities of up to 2400 cm2thinsp;Vminus;1thinsp;sminus;1at 77 K have been obtained with dgr; layers spaced 200 Aring; apart compared to a mobility of 280 cm2thinsp;Vminus;1thinsp;sminus;1for the single delta layer. The conductivity of the coupled dgr;hyphen;doped well exceeds that of comparable uniformly doped bulk layers, especially at lower temperatures. These types of structures show great promise in obtaining high mobilities with high carrier densities for semiconductors grown by simple homoepitaxy.