Complementary metal-oxide semiconductor-compatible detector materials with enhanced 1550 nm responsivity via Sn-doping of Ge/Si(100)

Abstract

Previously developed methods used to grow Ge1−ySny alloys on Si are extended to Sn concentrations in the 1019−1020 cm−3 range. These concentrations are shown to be sufficient to engineer large increases in the responsivity of detectors operating at 1550 nm. The dopant levels of Sn are incorporated at temperatures in the 370–390 °C range, yielding atomically smooth layers devoid of threading defects at high growth rates of 15–30 nm/min. These conditions are far more compatible with complementary metal-oxide semiconductor processing than the high growth and processing temperatures required to achieve the same responsivity via tensile strain in pure Ge on Si. A detailed study of a detector based on a Sn-doped Ge layer with 0.25% (1.1 × 1020 cm−3) Sn range demonstrates the responsivity enhancement and shows much better I-V characteristics than previously fabricated detectors based on Ge1−ySny alloys with y = 0.02.

GeSn/Ge heterostructure short-wave infrared photodetectors on silicon

“…However, combined with the recent progress in the integration of Ge photodetectors on Silicon-On-Insulator (SOI) for telecom-band applications [7], GeSn-based integrated photodetectors can become an attractive approach for monolithically integrated SWIR photodetectors. Moreover, recent results show that adding Sn in the p-i-n Ge detector matrix also increases the responsivity of the detector in the telecom wavelength range [8][9] and extends the cut-off wavelength beyond 1.7μm [10][11]. In this paper, we present photoconductive detectors based on a highly strained Ge 0.90 Sn 0.10 /relaxed Ge heterostructure grown on silicon with a cut-off wavelength of 2.4μm.…”

Influence of growth and annealing temperature on the strain and surface morphology of Ge995Sn0.005 epilayer

“…Kouvetakis et al [21,22] also showed that Sn concentration in the 10 19 ~ 10 20 cm -3 range was sufficient to largely increase the responsivity of detectors operating at 1550 nm. In this work, we grow Ge 1-x Sn x alloy with only 0.5% of Sn, which is within the maximum equilibrium solid solubility of Sn in Ge.…”

“…Despite these difficulties, high-quality Ge 1-x Sn x alloy has been grown by molecular beam epitaxy (MBE) [5][6][7][8][9][10] and chemical vapor deposition (CVD) [11][12][13]. Devices, such as LEDs [14][15][16] and photodetectors [17][18][19][20][21][22], have also been successfully fabricated.…”

Temperature-dependent direct transition energy in Ge0.99Sn0.01 film grown on Si measured by photoreflectance spectroscopy

“…The strain in the as-grown Ge 0.99 Sn 0.01 epitaxial layer was initially slightly compressive. However, the sample became fully relaxed after three times of the rapid thermal annealing treatment at a temperature of 750°C for 10 s, and then changed to slightly tensile strain upon cooling to room temperature due to the large difference in thermal expansion coefficients between Ge 0.99 Sn 0.01 and Si, with a final residual value of 0.16% according to high resolution X-ray diffraction (HRXRD) measurement [23,24]. The lattice dimensions of the films were also measured by HRXRD.…”