title: Low thermal-mass LEDs: size effect and limits.
abstract: In this work, low thermal-mass LEDs (LTM-LEDs) were developed and demonstrated in flip-chip configuration, studying both experimentally and theoretically the enhanced electrical and optical characteristics and the limits. LTM-LED chips in 25 × 25 μm2, 50 × 50 μm2, 100 × 100 μm2and 200 × 200 μm2mesa sizes were fabricated and comparatively investigated. Here it was revealed that both the electrical and optical properties are improved by the decreasing chip size due to the reduced thermal mass. With a smaller chip size (from 200 μm to 50 μm), the device generally presents higher current density against the bias and higher power density against the current density. However, the 25 × 25 μm2device behaves differently, limited by the fabrication margin limit of 10 μm. The underneath mechanisms of these observations are uncovered, and furthermore, based on the device model, it is proven that for a specific flip-chip fabrication process, the ideal size for LTM-LEDs with optimal power density performance can be identified.
authors.forename: Shunpeng
authors.initials: S
authors.lastname: Lu
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Zi-Hui
authors.initials: ZH
authors.lastname: Zhang
authors.forename: Swee Tiam
authors.initials: ST
authors.lastname: Tan
authors.forename: Zhengang
authors.initials: Z
authors.lastname: Ju
authors.forename: Yun
authors.initials: Y
authors.lastname: Ji
authors.forename: Xueliang
authors.initials: X
authors.lastname: Zhang
authors.forename: Yiping
authors.initials: Y
authors.lastname: Zhang
authors.forename: Binbin
authors.initials: B
authors.lastname: Zhu
authors.forename: Zabu
authors.initials: Z
authors.lastname: Kyaw
authors.forename: Namig
authors.initials: N
authors.lastname: Hasanov
authors.forename: Xiao Wei
authors.initials: XW
authors.lastname: Sun
authors.forename: Hilmi Volkan
authors.initials: HV
authors.lastname: Demir
mesh_terms: D004735:Energy Transfer; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006358:Hot Temperature; D008029:Lighting / Q000295:instrumentation*; D008904:Miniaturization; D012666:Semiconductors; D013696:Temperature