Gee, this identical (and I mean exact word for word) question was asked on Yahoo answers by "Andrew" a year ago.
Do have some kind of a model for the saturation current as a function of temperature? Min and max over what temprature range? Without more in the way of context, the question is meaningless.
A diode does not saturate. Instead it conducts or it does not conduct depending on the polarity. The forward voltage drop increases exponentially with increased current.
10nA is an extremely low current which is probably its reverse-biased leakage current.
The parameter \(I_S\) is the saturation current (though it is aften called the scale current). It is the reverse saturation current (what is often called the leakage current).