Characterization and Temperature Detection Application of Si-based Metal-Oxide-Semiconductor (MOS) Capacitors with Thin Dielectrics
Date Issued
2007
Date
2007
Author(s)
Wang, Tsung-Miau
DOI
en-US
Abstract
For MOS (n) capacitors, the saturation current is mainly attributed to the electron-hole pair recombination mechanism. But for MOS (p) capacitors, the saturation current is mainly attributed to the electron-hole pair generation mechanism, and is also controlled by interface trap densities (Dit), bulk traps, and suboxide. It can be examined by the electroluminescent (EL) method and their temperature dependencies. For the MOS (n) capacitors, because of the recombination mechanism, the EL phenomenon is easily found. However, for MOS (p) capacitors, because of the generation mechanism, the temperature response can be found. Furthermore, negative capacitance is found on a certain portion of MOS (n) C-V curves. It is probably in connection with the charge trapped and de-trapped in the interface and the charges have different phases. As the device size increasing, the negative capacitance is more obvious. For MOS (p) capacitors, the probability of soft breakdown (SBD) increases with temperature when biased in the saturation current region under substrate injection. The increase in the probability of SBD follows from the fact that increasing the temperature increases both the number of minority carriers and Dit, when the positive substrate injection region is biased. The amount of electrons near SiO2/Si interface will cause the percolation phenomenon effect. Therefore, the number of charges across the silicon dioxide increases so the voltage drop across the oxide increases, and finally SBD occurs. It is regarded as that the voltage will rearrange. The voltage rearrangement effect will damage the oxide films with a certain oxide thickness. We successfully demonstrated the temperature distribution on the 3-inch Si wafer by the conventional MOS (p) capacitors with pure SiO2 dielectrics. But when the thickness of SiO2 films increases slightly, the temperature sensitivity will decrease. It is not suitable for the application under low voltage operation. To do some improvement, the MOS (p) capacitors with hafnium oxide (HfO2) film added on SiO2 were demonstrated as reliable temperature-detecting devices for the first time. The saturation current of MOS (p) capacitor with added HfO2 film is easy to saturate within 0.5 V. Each increase of 10 °C almost doubles the saturation current. These devices are reliable even though they had been electrically stressed at various temperatures (30~90°C) for 4 hours. They are potential to be integrated into the circuits as temperature detectors for ultra large scaled integration technology
Subjects
金
氧半電容
空乏區
飽和電流
穿刺
效應
少數
載子
氧化鉿
MOS capacitors
depeletion region
saturation current
percolation phenomenon
minority carriers
hafnium oxideon
Type
thesis