In this paper, normal incidence vertical p-i-n photodetectors on a germanium-on-insulator(GOI) platform were demonstrated. The vertical p-i-n structure was realized by ion-implanting boron and arsenic at the bottom an...In this paper, normal incidence vertical p-i-n photodetectors on a germanium-on-insulator(GOI) platform were demonstrated. The vertical p-i-n structure was realized by ion-implanting boron and arsenic at the bottom and top of the Ge layer, respectively, during the GOI fabrication. Abrupt doping profiles were verified in the transferred high-quality Ge layer. The photodetectors exhibit a dark current density of ~47 mA∕cm^2 at-1 V and an optical responsivity of 0.39 A/W at 1550 nm, which are improved compared with state-of-the-art demonstrated GOI photodetectors. An internal quantum efficiency of ~97% indicates excellent carrier collection efficiency of the device. The photodetectors with mesa diameter of 60 μm exhibit a 3 dB bandwidth of ~1 GHz, which agrees well with theoretical calculations. The bandwidth is expected to improve to ~32 GHz with mesa diameter of 10 μm. This work could be similarly extended to GOI platforms with other intermediate layers and potentially enrich the functional diversity of GOI for near-infrared sensing and communication integrated with Ge CMOS and mid-infrared photonics.展开更多
Mechanical strain engineering has been promising for many integrated photonic applications. However,for the engineering of a material electronic bandgap,a trade-off exists between the strain uniformity and the integra...Mechanical strain engineering has been promising for many integrated photonic applications. However,for the engineering of a material electronic bandgap,a trade-off exists between the strain uniformity and the integration compatibility with photonic-integrated circuits (PICs). Herein,we adopted a straightforward recess-type design of a silicon nitride (SiNx) stressor to achieve a uniform strain with enhanced magnitude in the material of interest on PICs. Normal-incidence,uniformly 0.56% tensile strained germanium (Ge)-on-insulator (GOI) metal-semiconductor-metal photodiodes were demonstrated,using the recessed stressor with 750 MPa tensile stress. The device exhibits a responsivity of 1.840.15 A∕W at 1550 nm. The extracted Ge absorption coefficient is enhanced by -3.2×to 8340 cm^(-1) at 1612 nm and is superior to that of In_(0.53)Ga_(0.47)As up to 1630 nm limited by the measurement spectrum. Compared with the nonrecess strained device,additional absorption coefficient improvement of 10%–20% in the C-band and 40%–60% in the L-band was observed. This work facilitates the recessstrained GOI photodiodes for free-space PIC applications and paves the way for various (e.g.,Ge,GeSn or III-V based) uniformly strained photonic devices on PICs.展开更多
基金National Research Foundation Singapore(NRF)(NRF-CRP12-2013-04)Low Energy Electronic Systems(LEES)from the Singapore-MIT Alliance for Research and Technology Centre(SMART)Innovation Grant from SMART Innovation Centre(ING1510105-ENG)
文摘In this paper, normal incidence vertical p-i-n photodetectors on a germanium-on-insulator(GOI) platform were demonstrated. The vertical p-i-n structure was realized by ion-implanting boron and arsenic at the bottom and top of the Ge layer, respectively, during the GOI fabrication. Abrupt doping profiles were verified in the transferred high-quality Ge layer. The photodetectors exhibit a dark current density of ~47 mA∕cm^2 at-1 V and an optical responsivity of 0.39 A/W at 1550 nm, which are improved compared with state-of-the-art demonstrated GOI photodetectors. An internal quantum efficiency of ~97% indicates excellent carrier collection efficiency of the device. The photodetectors with mesa diameter of 60 μm exhibit a 3 dB bandwidth of ~1 GHz, which agrees well with theoretical calculations. The bandwidth is expected to improve to ~32 GHz with mesa diameter of 10 μm. This work could be similarly extended to GOI platforms with other intermediate layers and potentially enrich the functional diversity of GOI for near-infrared sensing and communication integrated with Ge CMOS and mid-infrared photonics.
基金National Research Foundation Singapore (NRFCRP19-2017-01)Ministry of Education-Singapore (AcRF Tier 1 (2019-T1-002-040 RG147/19 (S))Singapore-MIT Alliance for Research and Technology Centre (Low Energy Electronic Systems (LEES) IRG)。
文摘Mechanical strain engineering has been promising for many integrated photonic applications. However,for the engineering of a material electronic bandgap,a trade-off exists between the strain uniformity and the integration compatibility with photonic-integrated circuits (PICs). Herein,we adopted a straightforward recess-type design of a silicon nitride (SiNx) stressor to achieve a uniform strain with enhanced magnitude in the material of interest on PICs. Normal-incidence,uniformly 0.56% tensile strained germanium (Ge)-on-insulator (GOI) metal-semiconductor-metal photodiodes were demonstrated,using the recessed stressor with 750 MPa tensile stress. The device exhibits a responsivity of 1.840.15 A∕W at 1550 nm. The extracted Ge absorption coefficient is enhanced by -3.2×to 8340 cm^(-1) at 1612 nm and is superior to that of In_(0.53)Ga_(0.47)As up to 1630 nm limited by the measurement spectrum. Compared with the nonrecess strained device,additional absorption coefficient improvement of 10%–20% in the C-band and 40%–60% in the L-band was observed. This work facilitates the recessstrained GOI photodiodes for free-space PIC applications and paves the way for various (e.g.,Ge,GeSn or III-V based) uniformly strained photonic devices on PICs.
