Patent ID: 8619243

Claim:
A mobility measuring apparatus for measuring a mobility Î¼ of carriers in a semiconductor, comprising: a storage unit that stores a relationship between the mobility Î¼ and a decay constant Î³ of the carriers, a relationship between said decay constant Î³ and a carrier density N of said semiconductor and a relationship between a reflectivity R of said semiconductor to a terahertz light and said carrier density N, wherein said decay constant Î³ changes linearly relative to said carrier density N in said relationship between said decay constant Î¼ and a carrier density N; a light radiating unit that radiates a terahertz light to the semiconductor as a sample; a detecting unit that detects a reflected light of said sample to said radiated terahertz light; a reflectivity calculating unit that calculates a reflectivity R exp of said sample by determining a ratio of an intensity of said reflected light relative to an intensity of said radiated terahertz light; an obtaining unit that obtains a carrier density N exp of said sample corresponding to the reflectivity R exp of said sample by making reference to said stored relationship between said reflectivity R and said carrier density N and obtains a decay constant Î³ exp of said sample corresponding to said obtained carrier density N exp by making reference to said stored relationship between said carrier density N and said decay constant Î³, wherein said decay constant Î³ exp is calculated by detecting said decay constant Î³ that corresponds to said obtained carrier densit N exp in said relationship between said decay constant Î³ and a carrier density N, wherein said relationship between said decay constant Î³ and a carrier density N is obtained by fitting a plurality of plots of a relationship between said decay constant Î³ 0 and said carrier density N; and a mobility calculating unit that calculates said mobility Î¼ exp of said sample from said stored relationship between said mobility Î¼ and said decay constant Î³ on the basis of said obtained decay constant Î³ exp .