Optical Diagnostics and Imaging - Applied Optics Fundamentals and Device Applications - page 305

1 2 3

θ

n f

t

FIGURE 6.10
Interference measurement of dielectric film thickness.

6.10 OtherAnalysisTechniques
Angle polishing and staining is a technique enabling the observation of
material layers down to a thickness on the order of 100 Å (see Figure 6.11).
Surface profiling is accomplished with various profilometers. These devices
allow routine assessment of surface roughness to a resolution of 0.1 μm.
The electron microprobe is a device used to determine alloy composition
of AlGaAs materials in the indirect band gap regime (i.e., for percentages of
aluminum greater than approximately 45%). Hall and photo-Hall measure-
ments yield information on material carrier density and mobility.
Deep-level transient spectroscopy (DLTS) and capacitance-transient (C-T)
measurements are commonly used to provide a wide range of information

Y

X

10° = Ø

P-n junction

FIGURE 6.11
Measurement of junction depth by angle polishing and staining.