Microscopic study of the surfactant‐assisted Si, Ge epitaxial growth
The Sb‐assisted Si, Ge epitaxial growth processes have been studied using high resolution photoemission. It is found that the initially ordered Sb monolayer on the Si(100) and Ge(100) surfaces occupies the epitaxial sites and fully saturates the surface dangling bonds. This results in a reduction of the surface energy. During the growth process, the Sb atoms and the deposited Si, Ge atoms change their positions. Sb atoms segregate to the growth front to form a new ordered layer while leaving the uniform epitaxial Si, Ge layer behind.
The Surfactant Effect in Semiconductor Thin-Film Growth
This chapter discusses the effect of overlayers, commonly referred to as “surfactants,” on the epitaxial growth of semiconductors. Such overlayers make it possible to lower substantially the temperature required for growth of perfect epitaxial films. As device dimensions decrease, processing temperatures must be lowered to minimize diffusional broadening of interfaces and dopant profiles. Surfactants have been used to modify the growth mode of several systems, including metal layers in homoepitaxy and heteroepitaxy. The chapter also presents several theoretical models that explain the surfactant effect in semiconductor growth. These models may be divided into three categories. The first category comprises of models that concentrate on the microscopic aspects, attempting to understand the atomic-scale features and processes involved in this phenomenon. The second category comprises of models that are more concerned with the macroscopic aspects of the surfactant effect, such as island morphologies, distributions, and the effects of strain, without attempting to explain the details of the atomistic processes. The third category comprises of the models that attempt to combine both aspects (microscopic aspects and macroscopic aspects)—that is, they try to use realistic descriptions of the atomistic processes as the basis for macroscopic models.
Antimony adsorption on silicon
Abstract The kinetic behavior of antimony films adsorbed on clean silicon surfaces has been measured versus temperature and coverage using LEED, Auger and thermal desorption. Sb adsorbs in two distinct modes, seen in a high and a low temperature desorption peak. The high temperature peak fills up to one monolayer on the Si(111) surface with a desorption rate K D given by K D = K DO = exp(− K D / k T) N DS , with K DO = 1.5 × 10 9 s −1 , E D = 2.46 eV, and N DS = Sb coverage. Growth of this phase is two-dimensional. Higher Sb coverage adsorbs in the low temperature peak as bulk Sb on Sb with E D = 1.49 eV and grows without population limit in a three-dimensional mode. The residence time of Sb atoms on the surface, τ = K D −1 , varies from 10 5 to 10 s over the temperature range 600 to 950°C; this determines transient smearing during MBE growth of Si.