Direct detection of atomic arsenic desorption from Si(100)

Abstract

Application of the 118 nm single photon laser ionization technique to a molecular beam epitaxy machine is used for the first time to demonstrate direct desorption of As atoms from Si(100). Both As2 and As are the desorbing species from 1 ML of arsenic on silicon above 1000 K. This is in contrast to previously reported models that considered only dimer desorption. With a continuous flux of As4, the scattered and desorbing arsenic species from Si(100) are examined as a function of surface temperature (650–1200 K). Atomic desorption is large, 75%±19%, above 1000 K, and complete conversion of As4 to As2 and As occurs at 1200 K. The species selectivity of laser ionization time-of-flight mass spectroscopy has broader implications for GaAs growth.

Surface segregation of arsenic and phosphorus from buried layers during Si molecular beam epitaxy

“…r was calculated by curve fitting to the dopant decay profile ͑⌬͒. 11 In order to avoid out-diffusion of As during the annealing step, a thicker, 100 nm, buffer layer was grown at 650°C. Data from a previous study of P are also shown for comparison.…”

Arsenic surface segregation during in situ doped silicon and Si1−xGex molecular beam epitaxy

“…(4), it is possible to derive the value of the segregation energy, DG s , by measuring surface and bulk arsenic fractions in epilayers grown under near-equilibrium surface-segregation conditions. However, arsenic desorption from the silicon surface cannot be neglected at substrate temperatures above 600 1C [2,14]. This factor limits the accuracy of ex situ surface measurements in determining the surface composition, due to arsenic loss during substrate cooling.…”

Arsenic-Doped High-Resistivity-Silicon Epitaxial Layers for Integrating Low-Capacitance Diodes

“…Moreover, the desorption of the segregated atoms is enhanced by applying a high-temperature baking step prior to each new growth cycle. The desorption baking step has been characterized in several studies of situations where it is important to have precise control of the As covering the Si (100) surface [ 11 , 12 , 13 ]. Some of the results are shown in Figure 1 (a) where it can be seen that there is a strong temperature dependence of the desorption, while the effect saturates in time so that 20 min or 60 min at 850 °C give practically the same result.…”