Influence of encapsulation temperature on Ge:P delta-doped layers

Abstract

We present a systematic study of the influence of the encapsulationtemperature on dopant confinement and electrical properties of Ge:Pdelta-doped layers. For increasing growth temperature we observe anenhancement of the electrical properties accompanied by an increasedsegregation of the phosphorous donors, resulting in a slight broadeningof the delta layer. We demonstrate that a step-flow growth achieved atsimilar to 530 degrees C provides the best compromise between highcrystal quality and minimal dopant redistribution, with an electronmobility similar to 128 cm(2)/Vs at a carrier density 1.3x10(14)cm(-2), and a 4.2 K phase coherence length of similar to 180 nm.