Germanium-tin is an alloy of the elements germanium and tin, both located in group 14 of the periodic table. It is only thermodynamically stable under a small composition range. Despite this limitation, it has useful properties for band gap and strain engineering of silicon-integrated optoelectronic and microelectronic semiconductor devices.
Germanium-tin alloys must be kinetically stabilized in order to prevent decomposition. [1] [2] Therefore, low temperature molecular beam epitaxy or chemical vapor deposition techniques are typically used for their synthesis. [1]
Germanium-tin alloys have higher carrier mobilities than either silicon or germanium. Therefore it has been proposed that they can be used as a channel material in high speed metal-oxide-semiconductor field effect transistors. [3] In addition, the alloys' larger lattice constant relative to germanium makes it possible to use them as stressors to enhance the carrier mobility of germanium channel transistors. [3] [4]
At a Sn content beyond approximately 9%, germanium-tin alloys become direct gap semiconductors having efficient light emission suitable for the fabrication of lasers. [5] Since the constituent elements are chemically compatible with silicon, it is possible to integrate such lasers directly onto silicon microelectronic devices, enabling on-chip optical communication. This is still an active research area, but germanium-tin lasers operating at low temperatures have already been demonstrated. [6] [7] In addition, germanium-tin light emitting diodes operating at room temperature have also been reported. [8] [9]
Germanium-tin is an alloy of the elements germanium and tin, both located in group 14 of the periodic table. It is only thermodynamically stable under a small composition range. Despite this limitation, it has useful properties for band gap and strain engineering of silicon-integrated optoelectronic and microelectronic semiconductor devices.
Germanium-tin alloys must be kinetically stabilized in order to prevent decomposition. [1] [2] Therefore, low temperature molecular beam epitaxy or chemical vapor deposition techniques are typically used for their synthesis. [1]
Germanium-tin alloys have higher carrier mobilities than either silicon or germanium. Therefore it has been proposed that they can be used as a channel material in high speed metal-oxide-semiconductor field effect transistors. [3] In addition, the alloys' larger lattice constant relative to germanium makes it possible to use them as stressors to enhance the carrier mobility of germanium channel transistors. [3] [4]
At a Sn content beyond approximately 9%, germanium-tin alloys become direct gap semiconductors having efficient light emission suitable for the fabrication of lasers. [5] Since the constituent elements are chemically compatible with silicon, it is possible to integrate such lasers directly onto silicon microelectronic devices, enabling on-chip optical communication. This is still an active research area, but germanium-tin lasers operating at low temperatures have already been demonstrated. [6] [7] In addition, germanium-tin light emitting diodes operating at room temperature have also been reported. [8] [9]