Characteristics and parameter extraction for NiGe/n-type Ge Schottky diode with variable annealing temperatures

• Published in: Chinese physics B Vol. 19; no. 5; pp. 530 - 535
• Main Author: 刘红侠 吴笑峰 胡仕刚 石立春
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.05.2010
• Subjects: Annealing; Crystallization; Diodes; Germanium; Mathematical models; Nickel; Schottky diodes; Transport; 参数提取; 理想因子; 电流电压特性; 界面态密度; 肖特基二极管; 退火温度
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/19/5/057303

Current transport mechanism in Ni-germanide/n-type Ge Schottky diodes is investigated using current-voltage characterisation technique with annealing temperatures from 300 ℃ to 500℃. Based on the current transport model, a simple method to extract parameters of the NiGe/Ge diode is presented by using the I-V characteristics. Parameters of NiGe/n-type Ge Schottky diodes fabricated for testing in this paper are as follows： the ideality factor n, the series resistance Rs, the zero-field barrier height Фb0, the interface state density Dit, and the interracial layer capacitance Ci. It is found that the ideality factor n of the diode increases with the increase of annealing temperature. As the temperature increases, the interface defects from the sputtering damage and the penetration of metallic states into the Ge energy gap are passivated, thus improving the junction quality. However, the undesirable crystallisations of Ni-germanide are observed together with NiGe at a temperature higher than 400℃. Depositing a very thin （-1 nm） heavily Ge-doped n＋ Ge intermediate layer can improve the NiGe film morphology significantly.