Patent ID: 8446576
Filing Date: 2013-05-21
Classification: G01N,H01L

Abstract:
1. A carrier concentration measuring device that measures a carrier concentration of an impurity-doped inorganic compound semiconductor, comprising: a light radiation unit that irradiates the terahertz light to said inorganic compound semiconductor as a sample; a detection unit that detects reflected light of said inorganic compound semiconductor against said irradiated terahertz light; a computer containing storage that stores a correlation between reflectance of said inorganic compound semiconductor against terahertz light and said carrier concentration; said computer containing a processor that calculates an actual measurement value of the reflectance of said inorganic compound semiconductor by determining a ratio of intensity of said reflected light to intensity of said irradiated terahertz light, and refers to said stored correlation and reads the carrier concentration of said sample corresponding to the actual measurement value of said reflectance, wherein said processor sets measured reflectance as said reflectance against terahertz light of a measurement band in which the reflectance of said inorganic compound semiconductor against said terahertz light varies depending on said carrier concentration, said processor sets reference reflectance as said reflectance against terahertz light of a reference band in which said reflectance of said inorganic compound semiconductor against said terahertz light does not vary depending on said carrier concentration, said processor calculates a predicted reflectance ratio by comparing said measured reflectance with said reference reflectance, and said computer containing further storage that stores a correlation between said predicted reflectance ratio and said carrier concentration.