a method and apparatus measure the lifetime of a semiconductor material by directing microwave energy into the semiconductor material and by producing carriers within the semiconductor material by impinging light thereon . a non - metal material is interposed between the semiconductor material and a metallic surface , such that a portion of the microwave energy travels through the semiconductor material and the non - metal material and reflects off of the metallic surface and back through the non - metal material and the semiconductor material . additionally , a heating member is provided for heating the semiconductor material , whereby the lifetime of the semiconductor material is determined according to characteristics of the reflected microwave energy and the temperature of the semiconductor material .