Question

silicon wafers are sometime coated with thin layer of aluminium nitride at high temperature (1000 C)

coefficient of thermal expasion silicon crystal is significantly different than of aluminium nitride.

wil this cause a prolem explain? for silicon wafer?

Answer 1

Dear student!

Now a days, aluminium nitride (AIN) is widely used in coating over silicon wafer. Actually, its wurtzite phase (w-AlN) is a wide band gap (6.2 eV) semiconductor material which gives it a potential application for deep UV optoelectronics. It is stable at high temperatures in inert atmospheres and melts at 2800 °C.

So, it is used for surface acoustic wave sensors (SAWs) deposited on silicon wafers because of the piezoelectric properties.