| 摘要 |
PURPOSE:To measure and display an etching depth of a sample under test concurrently with a mass analysis of a measured element during measurement of depth and direction distributions of the density of impurities. CONSTITUTION:Primary ions generated by a duo-plasmatron are scanned electrically and radiated on a sample 2, which is etched in a rectangle with optional sizes. A Michelson interferometer is utilized as an optical system to measure the etching depth. A semiconductor laser capable of generating a light which is subject to interference is used as a light source. A beam from the light source 5 is split in two directions by means of a semitransparent mirror 7, then one of them, as a reference light, is reflected by a reflecting mirror 9, again going through the semitransparent mirror 7, and is converged on a light receiving face of a light detector 12. On the other hand, a distance measuring light 14 goes straight through the semitransparent mirror 7, and after being reflected by a sample etching face 2, again is reflected by the semitransparent mirror 7 and is converged on the light receiving face of the light detector 12. Therefore, every time the light passage difference between the distance measuring light 14 and the reference light 13 reaches an integer multiple of the wave length of the laser light, interference fringes containing brightness and darkness are generated on the light receiving face of the light detector 12 and the etching depth of the sample can be observed on the spot. |
