Atomic diffusion and interface electronic structure of III-V heterojunctions and their dependence on epitaxial growth transitions and annealing

 
 
 
 

Atomic diffusion and interface electronic structure of III-V heterojunctions and their dependence on epitaxial growth transitions and annealing

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Title: Atomic diffusion and interface electronic structure of III-V heterojunctions and their dependence on epitaxial growth transitions and annealing
Author: Smith, Phillip E.
Description: Achieving the abrupt interfaces necessary for III-V based devices presents a challenge in situations where both Group-III and Group-V sources are switched during an interface growth transition. Group-V exchange reactions and Group-III chamber memory effects are reported for a number of III-V systems. These phenomena, along with atomic rearrangements associated with cross-diffusion, can introduce interface-localized defects that adversely affect device performance. Additionally, the need to vary growth temperature with epilayer composition, as well as surface interactions during the early stages of interface growth, leads to differences between layer A grown on B versus layer B grown on A. The trend of device miniaturization and, correspondingly, high operating temperatures, makes understanding these interfacial interactions increasingly important. In order to clarify the role of chemical interactions and atomic rearrangement in determining interface electronic structure, cathodoluminescence spectroscopy (CLS), secondary ion mass spectrometry (SIMS), and a number of complementary techniques are used to perform measurements of representative, lattice-matched double heterostructures (DH) involving growth transitions with both cation and anion source-switching. The role of source-switching sequence and post-growth annealing in determining interface structure is quantified in InGaAs/InP, AlInP/GaAs, and InGaP/GaAs. I present evidence demonstrating that interface and bulk electronic structure depends sensitively on growth conditions, anneal temperature, and the resulting diffusion, thereby correlating cross-diffusion with defect emission and highlighting the asymmetric chemical and electronic differences due to growth sequence. Overall, these results demonstrate that interfacial cross-diffusion and exchange reactions have a significant impact on the electronic structure of lattice-matched III-V heterostructures.
Permanent Link: http://rave.ohiolink.edu/etdc/view?acc_num=osu1177957344
http://hdl.handle.net/2374.OX/7239
Date: 2007

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