Determination of critical film thickness of a compound semiconductor layer, and a method for manufacturing a semiconductor device using the method of determination

摘要

By applying the method, the critical film thickness of a compound semiconductor layer is determined, and a semiconductor device having a compound semiconductor layer with an optimized film thickness excellent in emitting performance is manufactured. The relationship between film thickness of a compound semiconductor layer and photoluminescence (PL) corresponding to the film thickness is obtained by measurement, the film thickness where PL exhibits a peak is designated as critical film thickness. The semiconductor layer comprises II-VI group compound semiconductor layer containing at least cadmium. The relationship between the critical film thickness and cadmium composition ratio is obtained by measurement. An equation which approximates the relationship between the critical film thickness and cadmium composition ratio is formulated. When a semiconductor device is manufactured, a compound semiconductor layer is formed so as that the thickness of the layer is thinner than the critical film thickness determined from the equation.