beginner's question: starting point for high T design

I am working with a deep submicron BiCMOS technology.
I did some high T measurement on BJT, and the collector-substrate leakage is 75 nA at 200 C and 1.7 uA at 300 C.
One of my workmates has already submitted a bandgap reference ckt using Brokaw cell. My cadence simulation shows that the output is 1.25 V with ~30 ppm from 25 C to 125 C. My target is to find some ckt workable at 200+ C, but my device model is accurate at T range from 25 to 125 C. I guess our bandgap ckt output won't be good at 200 C due to the BJT leakage. Can any ppl give me some suggestion on the "compensation" techniques?
I am also looking for opportunities for high T applications like PA, Mixer etc. Obviously the leakage is an issue there. It is a shame to tell I know nothing in IC design. Is there any simple test circuit for a begginer as a good starting point?

Shorse

Yes, some times it is better not to ask your colleagues because they can misunderstand that you're a beginner.

First of all: what do you call deep sub-micron? 0.25um or smaller?

The first clue is to have adecuate models. Are you working for industry or college? The question arises because in industry you are not allowed to make big errors (one shot design is desired) and you must rely on the validity of your models?

Do you have a characterization department?

Is it a bulk technology or SOI?

I know somebody that characterized a lot of technologies at high temp at college, so I could be able to get some models if you tell me in which you're interested.

See you

Thanks for your reply.
It is a 0.18 um technology, and I am working for college and I guess I won't worry too much about the error.
It is a bulk technology, and I don't know the best way to attack the leakage at high T.
Yes, I did a lot of high T measurement (DC +AC) on transistors, and I need high T model badly. It will be of great help if you give me a hint how to develope high T device models. I know only the basic skill to extract room temperature dev model.
thanks

Shorse