Infrared Light Source Made of Heavily Doped Single Crystal Silicon Microbridge

Abstract

We have developed an infrared light source made of a heavily doped single crystal silicon microbridge. This microbridge was formed by boron ion implantation and ammonia anisotropic etching. This infrared light source comprises a microheater. Accordingly infrared light is radiated from the heated microbridge. Because the ion implantation is possible to form a very thin layer of heavily doped single crystal silicon, the microheater has very small heat capacity. The size of the microheater is about 650×200×1.5μm³. It had a peak of radiant intensity at 4μm wavelength. Only 150mW drive power was consumed to raise the temperature of the microheater to 780°C. It had a small thermal time constant less than lmsec, and wide modulated temperature more than 700°C at 100Hz. Therefore, the infrared light source can radiate intermittent infrared light with direct electrical power drive. There is possibility that handy infrared sensing systems are realized.