Coulomb Blockade Effect of Carriers in nc-Si Embedded in Ultrathin SiO2 Films
镶嵌在超薄SiO_2层中的纳米硅的库仑阻塞现象

The nanocrystalline silicon (nc-Si) based double oxide barriers structures are fabricated in-situ by plasma oxidation and layer by layer technique in a plasma enhanced chemical vapor deposition (PECVD) system.The average grain size of nc-Si in this structure is about 6nm that is obtained from Raman spectrum.The nc-Si is firstly deposited on the tunneling oxide layer (2nm) and then oxided to form the gate oxide layer (5nm).The maximum capacitance of this structure at negative bias increased with decreasing frequency,which reflected the tunneling of holes between the nc-Si and the substrate through ultrathin tunneling oxide.Furthermore,two peaks in the low frequency capacitance curves,corresponding to the resonant tunneling of electrons into nc-Si,are observed.From the peaks in the low frequency (1kHz) C-V curves,the coulomb blockade energy (57meV) is estimated.