Current–voltage and low-frequency noise analysis of heterojunction diodes with various passivation layers

Publication date: Available online 4 December 2015
Source:Thin Solid Films
Author(s): Young-Uk Ko, Ho-Jin Yun, Kwang-Seok Jeong, Yu-Mi Kim, Seung-Dong Yang, Seong-Hyeon Kim, Jin-Sup Kim, Jin-Un An, Hi-Deok Lee, Ga-Won Lee
Low-frequency noise (1/f noise) has been analyzed to characterize the amorphous/crystalline silicon heterojunction diodes with passivation layer of a-Si:H (p-i-n), Al2O3 (p-Al2O3-n), and ZnO (p-ZnO-n) and without passivation (p-n). Four types of diodes show high ideality factors and the dependence of the reverse leakage current on the electric field shows that the diodes commonly follow the Poole-Frenkel model, which is field-assisted thermionic emission from the traps in the materials. However, the conduction mechanism in the reverse bias can be more easily clarified from the bias dependence of the 1/f noise. That is, the p-i-n, p-n diodes are affected by the diffusion current mechanism, and the p-Al2O3-n, p-ZnO-n diodes with an inferior interface are affected by the generation-recombination current mechanism. This indicates that the p-i-n and the p-n diodes have a better interface quality than the p-Al2O3-n and the p-ZnO-n. These results show that the 1/f noise measurement can be a useful and more sensitive method to estimate the interface quality of heterojunction diodes.