The accumulation-mode metal-oxide-semiconductor (MOS) capacitor is commonly employed to implement MOS varactors in frequency-tuning circuits for radio frequency (RF) and analog applications. A subcircuit model for the accumulation-mode MOS (AMOS) capacitor based on the Berkeley Short-channel IGFET Model (BSIM) for the MOS field effect transistor (MOSFET) is presented. The proposed model accurately fits the capacitance-voltage (C-V) characteristics of an AMOS capacitor fabricated in a submicron CMOS process over the full range of operating gate voltages. The model also accounts for the impact of the distributed series resistance on the transient response of the AMOS capacitor. Notably, the gate capacitance and the associated series resistance are modeled as a distributed resistor-capacitor (RC) network to derive a subcircuit-based model with the bias-dependent resistance of the accumulation layer modeled as a voltage-controlled resistor (VCR). The proposed model is evaluated based on SPICE simulation of the intrinsic transient response of the AMOS capacitor using a basic circuit, representing the distributed RC network associated with the MOS device structure. Fine tuning of the effective series resistance in the subcircuit model can be achieved by fitting the measured data characterizing the charge–discharge behavior of the AMOS capacitor to the simulated data characterizing the intrinsic transient response generated by SPICE.

累积模式金属氧化物半导体 (MOS) 电容器通常用于在射频 (RF) 和模拟应用的频率调谐电路中实现 MOS 变容二极管。提出了基于 MOS 场效应晶体管 (MOSFET) 的伯克利短沟道 IGFET 模型 (BSIM) 的累积模式 MOS (AMOS) 电容器的子电路模型。所提出的模型在整个工作栅极电压范围内准确地拟合了在亚微米 CMOS 工艺中制造的 AMOS 电容器的电容-电压 (CV) 特性。该模型还考虑了分布式串联电阻对 AMOS 电容器瞬态响应的影响。尤其，栅极电容和相关联的串联电阻被建模为分布式电阻电容 (RC) 网络，以导出基于子电路的模型，其中累积层的偏置相关电阻被建模为压控电阻 (VCR)。所提出的模型基于使用基本电路对 AMOS 电容器的固有瞬态响应进行 SPICE 仿真进行评估，代表与 MOS 器件结构相关的分布式 RC 网络。通过将表征 AMOS 电容器充放电行为的测量数据拟合到表征 SPICE 生成的固有瞬态响应的模拟数据，可以实现子电路模型中有效串联电阻的微调。所提出的模型基于使用基本电路对 AMOS 电容器的固有瞬态响应进行 SPICE 仿真进行评估，代表与 MOS 器件结构相关的分布式 RC 网络。通过将表征 AMOS 电容器充放电行为的测量数据拟合到表征 SPICE 生成的固有瞬态响应的模拟数据，可以实现子电路模型中有效串联电阻的微调。所提出的模型基于使用基本电路对 AMOS 电容器的固有瞬态响应进行 SPICE 仿真进行评估，代表与 MOS 器件结构相关的分布式 RC 网络。通过将表征 AMOS 电容器充放电行为的测量数据拟合到表征 SPICE 生成的固有瞬态响应的模拟数据，可以实现子电路模型中有效串联电阻的微调。