本文研究了原子层化学气相淀积ALCVD(atom layer chemical vapor deposition)方法淀积的HfO2/SiO2/p-SiMOS电容的电特性.高频时,积累电容出现了频率色散现象.针对双频C-V法测量超薄HfO2/SiO2堆栈栅MOS电容中制备工艺和测量设备引入的寄生效应,给出了改进的等效电路模型,消除了频率色散.研究发现,高k介质中存在的缺陷和SiO2/Si处的界面态,使高频C-V特性发生漂移.对禁带中界面态的分布进行归纳,得到C-V曲线形变的规律.研究了形变的C-V曲线与理想C-V特性的偏离,给出了界面态电荷密度的分布,得到了相对于实测C-V曲线的矫正线.通过比较理想C-V曲线和矫正线,提取了平带电压、栅氧化层电荷、SiO2/Si界面的界面态密度等典型的电学参数.
A compact drain current including the variation of barrier heights and carrier quantization in ultrathin-body and double-gate Schottky barrier MOSFETs （UTBDG SBFETs） is developed. In this model, Schrodinger＇s equation is solved using the triangular potential well approximation. The carrier density thus obtained is included in the space charge density to obtain quantum carrier confinement effects in the modeling of thin-body devices. Due to the quantum effects, the first subband is higher than the conduction band edge, which is equivalent to the band gap widening. Thus, the barrier heights at the source and drain increase and the carrier concentration decreases as the drain current decreases. The drawback of the existing models,which cannot present an accurate prediction of the drain current because they mainly consider the effects of Schottky barrier lowering （SBL） due to image forces,is eliminated. Our research results suggest that for small nonnegative Schottky barrier （SB） heights,even for zero barrier height, the tunneling current also plays a role in the total on-state currents. Verification of the present model was carried out by the device numerical simulator-Silvaco and showed good agreement.
