1. NOIMOD. 
It  is a model flag,  which used to select different combination of flicker and thermal noise models.Default value is 1.

2. Flicker Noise Modeling.
There exist two models for flicker noise modeling. One is called SPICE2 flicker noise model; the other is BSIM3 flicker noise model [35-36]. The flicker noise model parameters are listed here:


The formulations for SPICE2 model is expressed as (f is the frequency):
                                 

The formulations for BSIM3 model is expressed as (f is the frequency):
(1). If Vgs > Vth +1

where Vtm is the thermal voltage, µeff is the effective mobiity at the given bias condition, and Leff and Weff are the effective channel length and width, respectively. The parameter  N0 is the charge density at the source side given by
                               
The parameter Nl is the charge density at the drain end given by
                               
∆Lclm is the channel length reduction due to channel length modulation and given by
                                

(1). Otherwise 
                               
Where, Slimit  is the flicker noise calculated at Vgs = Vth + 0.1 and Swi is given
by
                               

3. Channel Thermal Noise Modeling
There also exist two models for channel thermal noise modeling. One is called SPICE2 thermal noise model. The other is BSIM3v3 thermal noise model.

题外话，从TSMC得到的库文件里NOIMOD=2，也就是说TSMC对两种噪声都是使用的BSIM模型。而MOSIS网站给出的那些TSMC的工艺文件中是不包括任何噪声参数的，如果要使用这些文件进行噪声性能仿真的最简单的办法就是手工加入NOIMOD=1并给出Kf参数，比如KF=4.5E-29 （NMOS）KF=1.3E-29（PMOS）。

[Reference] BSIM3v3.2.2 MOSFET Model Users’ Manual, 1999.