Optimized InAlAs graded buffer and tensile-strained dislocation filter layer for high quality InAs photodetector grown on Si

Geunhwan Ryu, Seungwan Woo, Soo Seok Kang, Rafael Jumar Chu, Jae Hoon Han, In Hwan Lee, Daehwan Jung, Won Jun Choi

Research output: Contribution to journalArticlepeer-review

Abstract

We demonstrate a low threading dislocation density (TDD) and smooth surface InAs layer epitaxially grown on Si by suppressing phase separation of InxAl1-xAs (x = 0 to 1) graded buffer and by inserting a tensile-strained In0.95Al0.05As dislocation filter layer. While keeping the total III-V layer below 2.7 μm to avoid thermal cracks, we have achieved a sixfold reduction of TDD in InAs on Si compared to the unoptimized structure. We found a strong correlation between the metamorphic InAs surface roughness and TDD as a function of InxAl1-xAs buffer thickness. An optimal thickness of 175 nm was obtained where both phase separation and 3D islanding growth were suppressed. Moreover, a tensile-strained In0.95Al0.05As dislocation filter layer and high growth temperature of the InAs cap layer further assisted the dislocation reduction process, which led to a TDD to 1.37 × 108 cm-2. Finally, an InAs p-i-n photodetector grown on the optimized InAs/Si template confirmed its high quality by showing an improved responsivity from 0.16 to 0.32 A/W at a 2 μm wavelength.

Original languageEnglish
Article number262106
JournalApplied Physics Letters
Volume117
Issue number26
DOIs
Publication statusPublished - 2020 Dec 28

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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