Towards simultaneous achievement of carrier activation and crystallinity in Ge and GeSn with heated phosphorus ion implantation: An optical study

Abstract

We have investigated the optical properties of Ge and GeSn alloys implanted with phosphorus ions at 400 °C by spectroscopic ellipsometry from far-infrared to ultraviolet. The dielectric response of heated GeSn implants displays structural and transport properties similar to those of heated Ge implants. The far-infrared dielectric function of as-implanted Ge and GeSn shows the typical free carrier response which can be described by a single Drude oscillator. Bulk Ge-like critical points E1, E1 + Δ1, E0', and E2 are observed in the visible-UV dielectric function of heated Ge and GeSn indicating single crystalline quality of the as-implanted layers. Although the implantation at 400 °C recovers crystallinity in both Ge and GeSn, an annealing step is necessary to enhance the carrier activation.

70 °C synthesis of high-Sn content (25%) GeSn on insulator by Sn-induced crystallization of amorphous Ge

“…In particular, 70 C annealing allows for an extremely high Sn composition of nearly 25%. Considering the relationship between the growth temperature and the Sn composition of GeSn, this result is consistent with the previous reports on GeSn grown by MBE [10][11][12][13][14][15][16] or CVD. [17][18][19] We evaluated the surface structure of GeSn formed at 70 C by using scanning electron microscopy (SEM) with an energy dispersive X-ray spectrometer (EDX) and an electron backscatter diffraction (EBSD) detector.…”

Large area Germanium Tin nanometer optical film coatings on highly flexible aluminum substrates

“…Additionally, the lattice constant of GeSn can be tuned by varying the Sn composition to allow for heteroepitial growth of multifunctitonal heterostructures 12 13 . Since the solubility limit of Sn in Ge is relatively low, i.e., ~1%, low temperature molecular beam epitaxy (MBE) and chemical vapor deposition (CVD) techniques have been developed to realize the growth of GeSn films with high Sn composition 14 15 . Recently, K. Toko deposited polycrystalline GeSn with Sn composition exceeding 25% on flexible plastic substrates at a extremely low temperature of 70 °C 16 .…”

Defect engineering for shallow n‐type junctions in germanium: Facts and fiction

“…A possible solution to this problem is the use of so‐called hot implants , which have the advantage to suppress the damage formation by dynamic annealing, making it harder to amorphize the material. Initial studies on 400 °C P implantation in Ge and GeSn indicate that damage annealing occurs but an additional annealing step is required to enhance the dopant activation . Other studies revealed that for a 10 keV As + implantation at a dose of 1 × 10 15 at cm −2 and 400 °C, a residual amorphous Ge layer has been found, however, much smaller than for the room temperature reference condition .…”