2.and I know HSPICE has many parameters for BJT. If I used a model like what I just describe what would happen to the parameters I do not define? is there any default value for them?
A BC107 was made 45 years ago!
Then I worked for Philips and I still have a few of them in the old fashioned metal case.
Spice was not invented then but the spec's for a modern BC547 are the same.