[ noun ] a material such as glass or porcelain with negligible electrical or thermal conductivity <noun.substance>
Insulator \In"su*la`tor\, n. 1. One who, or that which, insulates.
2. (Elec. & Thermotics) A substance or object that insulates; a nonconductor; as, polyurethane foam is a popular thermal insulator. [1913 Webster +PJC]
But as the transistors get smaller, the part of the chip taken up by isolation becomes excessive, so a new solution had to be found. A number of companies now believe the answer is to put a layer of insulator under the transistors.
The insulator protects the thermocouples from chemical attack, while its density and thermal conductivity allow the same response times as a bare wire of the same diameter. Cableries de Lens: France, tel 3327671111; fax 3327686077.