The Growth of AIGaAs/GaAs Heterostructures By Atomic Layer Epitaxy

Abstract

The kinetics of atomic layer epitaxy (ALE) of GaAs utilizing trimethylgallium and arsine are described. The results show that saturated monolayer growth can be achieved-in the temperature range 445°C -485°C and that high quality materials can be grown.. Hybrid A1GaAs/GaAs heterostructures have been grown utilizing ALE for the active regions and conventional metalorganic chemical vapor deposition (MOCVD) for the confining regions that yield high quality quantum wells and low threshold quantum well lasers.

Low temperature metal-organic chemical vapor deposition growth processes for high-efficiency solar cells

“…These benefits have led to cm-*, which is red shifted with respect to its value of 2122 I the investigation of alternative arsenic sources to replace cm "* in the arsine molecule. Based upon this observation arsine (1)(2)(3)(4) Temp(=C)' and ethylene (C=I-L_ are observed to be the main reaction products. In addition, a small quantity of arsine at 2122 Fig.6.…”

“…dC plains the formation of DEAsH from the thermal decomdtkC [3] position of TEAs. This can be described by the lo]lowing expression where C is the concentration of reactant, t is reaction time, (C_.Hs)_s -* (C_H_)_AsH + C=H_ (350°-430°C) [2] and k is an effective rate constant of the form Figure 5 shows the relative concentration of the gaseous k = A exp (-E^/RT) [4] species as a function of temperature in the hot zone. Since The pre-exponential factor is the absolute rate and has the vapor pressure of DEAsH is not known, the concentra, units ofs -t and E^is the activation energy for the reaction, tion of DEAsH was estimated by taking the IR absorptiv.…”

“…[7] and H. C. Lee, J. Crystal Growth, 77, 188 (1986) (1) one monolayer of AX gaseous precursor is chemisorbed on surface, excess AX molecules can only physisorb and evaporate off above a critical temperature, (2) reactor is purged with inert gas (H2), (3) precursor BY is injected and forms a complete monolayer by a surface exchange reaction, (4) reactor is purged in preparation for repeat of cycle. GaAs wafers are arranged in rectangular quartz boat to insure maximum maximum interaction with sampled gas stream.…”

“…They derived, along with the activation energy for the rupture of the second Ga-methyl bond, an extremely low pre-exponential factor ( 8.7x107 sec-1) for a first order unimolecular reaction that is inconsistent with theoretical expectations[li and awaits a closer examination. TMGa thermal decomposition was further studied by infrared spectroscopy(IR) [2]-- [6], mass spectroscopy [7]-- [11], and laser induced fluorescence (LIF) [12]. From the decrease in the mole fraction of TMGa as a function of temperature, DenBaars et al were able to determine the activation energy for the rupture of the first Ga-methyl bond to be 58---62 kcal/mol.…”

“…By using the following first order adsorption expression we can effectively describe the the ALE growth rate: between compound reactants: (1) one monolayer of AX gaseous precursor is chemisorbed on surface, excess AX molecules can only physisorb and evaporate off above a critical temperature, (2) reactor is purged with inert gas (H2), (3) precursor BY is injected and fbrms a complete monolaycr by a surface exchange reaction, (4) reactor is purged in preparation for repeat of cycle. The first research on ALE was done in the II-VI semiconductor system, The most widespread commorcial application of ALE has been the growth of ZnS for use in AC clectroluminescent displaypanels.…”