Characterization in Silicon Processing

The best technique

is

scanning tunneling microscopy

(STM),

which

can map

out

the

localized surface

and

produce images

and

quantitative roughness factors

characteristic

of

a surface morphology (see Figure 5.2).

The

range

and

frequency

of

the feature sizes

can be

determined from

the

data

and can be

correlated back

to

reflectivity

measurements.

The

area examined with this technique

is

small,

so

sev-

eral

measurements across

the

sample must

be

done

to

insure

the

correct repre-

sentation

of

the surface

is

found. Figure

5.3

shows

that

the

reflectivity

of

the films

correlates

directly

to the

deposition regime,

that

is, whether

it is

surface reaction ...