Effect of Si/Si_l-yC_y/Si Barriers on the Characteristics of Si_l-xGe_x/Si Resonant Tunneling Structures

P-type double barrier resonant tunneling diodes (RTD) with the single Si_0.6Ge_0.4 quantum well and double Si_0.6Ge_0.4spacer have been realized by using an ultra clean low-pressure chemical vapor deposition system. The effect of Si_1-yC_y layer on the characteristics of the devices was shown by comparing the current-voltage (I-V) characteristics of RTD’s of the barriers of Si layers with that of Si/ Si_1-yC_y/Si structures. The peak voltage was gradually increased and the resonant current decreased obviously with increasing C content in the Si/ Si_1-yC_y/Si barriers. The origin of the phenomena above can be attributed to the C related deep acceptor levels in the Si/ Si_1-yC_y/Si barriers. The possible mechanism for the observed I- V characteristics was shown more clearly by increasing C content to 3% and changing the thicknesses of Si and Si_1-yC_y layers in the Si/Si_1-yC_y/Si barriers.