Characterization of high-purity arsine and gallium arsenide epilayers grown by MOCVD

• Published in: Journal of crystal growth 2008-11, Vol.310 (23), p.4780-4785
• Main Authors: Feng, Jun, Clement, Ryan, Raynor, Mark
• Format: Article
• Language: English
• Subjects: A1. High purity; A1. Impurities; A1. Low temperature photoluminescence; A1. Purification; A3. Metal organic chemical vapor deposition; B2. Arsine; B2. GaAs; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Photoluminescence; Physics; Solid surfaces and solid-solid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2008.08.023

Impurities present in the metal organic chemical vapor deposition (MOCVD) process gases and precursors can have a significant effect on the performance of III–V compound semiconductor devices. High-purity arsine purified using chemical, adsorption and distillation techniques, has been characterized for impurities by using high sensitivity gas analysis methods and low temperature photoluminescence (PL) of GaAs epilayers. Permanent gas, hydrocarbon and dopant impurities can all be removed using these purification methods to below the detection limit of instrumentation (low nmol mol −1–pmol mol −1, depending on method). Capability to remove water vapor to single digit nmol mol −1 levels is also demonstrated and cylinder depletion studies show that gas-phase arsine, with consistently low H 2O, can be delivered from the cylinder, even well after phase break. Low temperature PL measurements are made on 10 μm GaAs/GaAs grown with three different arsine sources. Well-resolved near-band emission characteristics of high-purity n-type GaAs is obtained with high-purity distilled arsine. PL of epilayers grown with less pure arsine show the presence of Ge as well as elevated levels of Mg and Zn, incorporated from the trimethylgallium. The incorporation of O from an arsine cylinder containing H 2O at 200 nmol mol −1 results in reduced full width at half maximum (FWHM) of the near-band emission and decreased ( D 0, X) and ( F, X) intensity, highlighting the importance of minimizing H 2O impurity.