TY - JOUR
T1 - Uniformity of improved high-quality GaAs and AlGaAs epilayers and Schottky barriers prepared by molecular beam epitaxy
AU - Missous, M.
PY - 1992/12/1
Y1 - 1992/12/1
N2 - The growth by molecular beam epitaxy (MBE) of GaAs and AlGaAs, although a well controlled process, has nevertheless suffered from poor reproducibility and uniformity across large substrates (greater than 2 inch) as would be required in practice for the fabrication of devices, the MESFET being a point in case. Recent advances in the design of MBE deposition chambers coupled with the availability of high-purity starting source materials have enabled the growth of unprecedentedly high-quality, very uniform GaAs and AlGaAs with electronic defect densities below 1014 cm-3, even for the highly reactive AlAs binary, and with a compositional uniformity for the ternary alloy (AlGaAs) of better than +or-0.5%, corresponding to temperature variations of less than 1 degrees C at 700 degrees C. The design of a new Ga hot-lip cell in the VG V90H MBE system has enabled total structural defects of less than 400 cm-2 to be routinely achieved on 2 inch substrates. The ability to deposit well characterised single-crystal Al films on GaAs and AlGaAs has also led to a new dimension in the reproducibility and control of near-ideal Schottky diodes for MESFET and HEMT applications. The advantages of such structures include uniformities of better than +or-5 meV in the barrier height across 2 inch substrates and thermal stabilities up to 500 degrees C. The practical significance of these results will be emphasised for the GaAs-AlGaAs system.
AB - The growth by molecular beam epitaxy (MBE) of GaAs and AlGaAs, although a well controlled process, has nevertheless suffered from poor reproducibility and uniformity across large substrates (greater than 2 inch) as would be required in practice for the fabrication of devices, the MESFET being a point in case. Recent advances in the design of MBE deposition chambers coupled with the availability of high-purity starting source materials have enabled the growth of unprecedentedly high-quality, very uniform GaAs and AlGaAs with electronic defect densities below 1014 cm-3, even for the highly reactive AlAs binary, and with a compositional uniformity for the ternary alloy (AlGaAs) of better than +or-0.5%, corresponding to temperature variations of less than 1 degrees C at 700 degrees C. The design of a new Ga hot-lip cell in the VG V90H MBE system has enabled total structural defects of less than 400 cm-2 to be routinely achieved on 2 inch substrates. The ability to deposit well characterised single-crystal Al films on GaAs and AlGaAs has also led to a new dimension in the reproducibility and control of near-ideal Schottky diodes for MESFET and HEMT applications. The advantages of such structures include uniformities of better than +or-5 meV in the barrier height across 2 inch substrates and thermal stabilities up to 500 degrees C. The practical significance of these results will be emphasised for the GaAs-AlGaAs system.
UR - http://www.scopus.com/inward/record.url?scp=0026626254&partnerID=8YFLogxK
U2 - 10.1088/0268-1242/7/1A/048
DO - 10.1088/0268-1242/7/1A/048
M3 - Article
AN - SCOPUS:0026626254
SN - 0268-1242
VL - 7
SP - A249-A254
JO - Semiconductor Science and Technology
JF - Semiconductor Science and Technology
IS - 1 A
M1 - 048
ER -