Ultra-high-speed lateral solid phase crystallization of GeSn on insulator combined with Sn-melting-induced seeding

Abstract

To produce high-performance devices on flexible plastic substrates, it is essential to form Ge-based group IV semiconductors on insulating substrates at low temperatures (≤250 °C). We have developed a technique for solid phase crystallization of amorphous GeSn (≤220 °C) enhanced by Sn doping, and combined with a seeding technique induced by Sn melting (∼250 °C). This combination produces lateral crystallization of amorphous GeSn from seed arrays with no incubation time. As a result, extremely high growth velocities at 220 °C, depending on Sn concentration, e.g., 0.13 μm/h (14% Sn) and 1100 μm/h (23% Sn), are achieved. These velocities are 104–108 times higher than that of pure Ge. This technique enables growth of crystalline GeSn island arrays (diameters: 50–150 μm) at low temperatures (≤250 °C) at controlled positions on insulating substrates.

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

“…[23][24][25][26] More recently, the study of GeSn on insulators (GSOIs) has been accelerated for fabricating monolithically integrated GeSn-based devices on three-dimensional Si largescale integrated circuits and on multi-functional displays with glass or plastic substrates. [27][28][29][30][31][32] In particular, the Sninduced crystallization of amorphous (a-) Ge(Sn) has garnered attention. [30][31][32] This technique produced polycrystalline (poly-) GSOIs at low temperatures (150-475 C) by using Sn as a catalyst; however, the Sn compositions in GeSn were still low.…”

“…[27][28][29][30][31][32] In particular, the Sninduced crystallization of amorphous (a-) Ge(Sn) has garnered attention. [30][31][32] This technique produced polycrystalline (poly-) GSOIs at low temperatures (150-475 C) by using Sn as a catalyst; however, the Sn compositions in GeSn were still low. In the present study, we investigated the Sninduced crystallization of a-Ge focusing on the relation between the growth temperature and the Sn composition in GeSn.…”

Wafer-scale all-epitaxial GeSn-on-insulator on Si(1 1 1) by molecular beam epitaxy

“…Naturally, the next step in GeSn-technology is the development of GeSn-on-insulator (GeSnOI) substrates, which is expected to combine the attractive material characteristics of the alloy with the "on-insulator" advantages [17]. However, the GeSnOI technology is still in its nascent stage, with only a few investigations reported so far [18][19][20][21][22][23][24].…”

Sn-inserted Al-induced layer exchange for large-grained GeSn thin films on insulator

“…The study of GeSn on insulators (GSOIs) has been accelerated for fabricating monolithically integrated GeSn-based devices on three-dimensional Si large-scale integrated circuits and on multi-functional displays with glass or plastic substrates [17][18][19][20][21][22][23][24][25][26].…”

“…The incorporation of 2% Sn into Ge passivated the vacancy defects or reduced the grain boundary scattering, resulting in the higher carrier mobilities than Ge [18,19]. The tin-induced crystallization (TIC) of amorphous Ge (a-Ge) has recently garnered attention [23][24][25][26]. We controlled the Sn content in the resulting polycrystalline (poly-) GeSn by tuning the TIC temperature and achieved high-Sn (25%) content poly-GeSn on glass at 70 °C [26].…”