Ambipolar germanium nanowire transistors and their nonvolatile memory applications

• Main Authors: Chao-Fu Chen, 陳昭福
• Other Authors: Ming-Der Lan
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/chqe54

碩士 === 國立中興大學 === 物理學系所 === 103 === Germanium (Ge) has recently re-gained significant amount of interests in the semiconductor research and industrial community due to its great potential and distinct characteristics in nature. High carrier mobility makes germanium become much better channel material for developing high-performance field effect transistors (FETs). Besides, its Bohr radius of 24.3 nm is much larger than that of Si (4.9 nm), which implies that quantum confinement effects will be more essential in further nanoelectronics. Herein, Ge nanowries (NWs) with an average diameter of 70 nm were investigated. Standard electron-beam lithography and thermal evaporation were used to fabricate Ge NW FETs. To improve electrical contacts between Ge NW and Cu electrodes, the as-made FETs were suffered from a post-annealing process at 150 OC for 30 mins in high vacuum. Surprisingly, the ambiopolar charge transport has been observed in the Ge NW FETs for the first time. Such an ambipolarity can be mainly ascribed to the formation of Schottaky barriers in both NW-electrode contacts. Besides, a non-ignored hysteresis loop with a memory windows up to 70 V has been observed in transfer characteristics and then Ge-NWs-based nonvolatile memories have been realized.