Improved Carrier Mobility of Sn-Doped Ge Thin-Films (≤50 nm) by Interface-Modulated Solid-Phase Crystallization Combined with Thinning

摘要

A technique to obtain high carrier mobility of Sn-doped Ge thin-films (thickness ≤50 nm) on insulator is proposed. The carrier mobilities of Ge films grown by interface-modulated solid-phase crystallization decrease with decreasing deposition thickness. From crystal structure analysis, it is revealed that decrease in the grain sizes with decreasing deposition thickness causes the decrease of the mobilities. To solve this problem, we propose thinning of grown films (deposition thickness: 50 nm) by etching. This achieves high carrier mobility (~170 cm²/Vs) even for thin-films (thickness: 20 nm). This technique will be useful to realize advanced fully-depleted devices for next-generation electronics.