Both suggestions are good but in industry we use either "J" or "K" thermocouples with "K" being the most common where I work. If the temperature was around the boiling point of water I would recommend a RTD.
I just read you post without reading the replys. If a IC is so hot that you cannot place your finger on it for over 1 second, it is too hot! You either have a heat sink problem or a bad IC.
Ummm, no. He doesn't wish to remove heat away from a part that is used as a sensor to meause temperature. His problem is that he is looking for something that most likely doesn't exist. He has admitted that he is unable to find it so he has been given a couple of choices. 350 degrees is far from the boiling point of water.