TY - JOUR
T1 - Reduction of visible defect densities in molecular beam epitaxy grown GaAs using a high-capacity, low flux transient Ga source with novel crucible inserts
AU - Sacks, R. N.
AU - Patterson, George A.
AU - Stair, Kathleen A.
PY - 1996/5/1
Y1 - 1996/5/1
N2 - A new design of large capacity crucible with novel inserts has been evaluated with respect to visible defect density, layer uniformity, and flux transient. The crucible was tested in a commercially available furnace with two independently controlled heater windings. The inserts were two disks, each having a different set of holes, stacked inside the crucible and permitting no line of sight between the Ga melt and the substrate. The source was tested side-by-side with a similar furnace equipped with a commercially available crucible and conical insert set designed for low shutter transient and low flux drift. Defect densities were measured on epitaxial layer structures having a total of 1 μm of GaAs. The new design showed significantly lower total defect densities than a control growth with the standard cell, producing as few as ∼ 1/3 the defects (43±6 vs 155/cm2). Flux transients were the same with the two sources (<2%). Uniformity was tested by using photoluminescence to measure the thickness of GaAs quantum wells across a 75 mm diameter wafer. While the old design produces a center-to-edge decrease in thickness of ∼2.5%, the new source produces a decrease in thickness of ∼6.5%.
AB - A new design of large capacity crucible with novel inserts has been evaluated with respect to visible defect density, layer uniformity, and flux transient. The crucible was tested in a commercially available furnace with two independently controlled heater windings. The inserts were two disks, each having a different set of holes, stacked inside the crucible and permitting no line of sight between the Ga melt and the substrate. The source was tested side-by-side with a similar furnace equipped with a commercially available crucible and conical insert set designed for low shutter transient and low flux drift. Defect densities were measured on epitaxial layer structures having a total of 1 μm of GaAs. The new design showed significantly lower total defect densities than a control growth with the standard cell, producing as few as ∼ 1/3 the defects (43±6 vs 155/cm2). Flux transients were the same with the two sources (<2%). Uniformity was tested by using photoluminescence to measure the thickness of GaAs quantum wells across a 75 mm diameter wafer. While the old design produces a center-to-edge decrease in thickness of ∼2.5%, the new source produces a decrease in thickness of ∼6.5%.
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M3 - Article
AN - SCOPUS:5544265106
SN - 1071-1023
VL - 14
SP - 2187
EP - 2191
JO - Journal of Vacuum Science & Technology B: Microelectronics Processing and Phenomena
JF - Journal of Vacuum Science & Technology B: Microelectronics Processing and Phenomena
IS - 3
ER -