11 Application of Accelerators and Storage Rings
703
Fig. 11.20 Present and
future high energy
implantation [35]
The implantation can be used not only for elemental semiconductors, but also
for compound semiconductors as GaAs, InP or superlattices. Figure 11.20 shows
diagrammatically the whole field as dose dependent on ion energy [34]. To increase
the performance of high power devices high energy ion beam irradiation is also used
to reduce the charge carrier life time. In contracts to the common used life-time
killing with electron beams, the damage area of ions is concentrated at the Bragg
peak. This allows the reduction of the carrier concentration without a changing of
the main electrical specification of the device.
Accelerators used for that work are van de Graaff accelerators, dynamitrons and
in increasing number also RFQs. In all these types of accelerators the controllability
of the ion energy is one of the major advantages.
11.2.3.2 Analysis of Materials
The analysis of materials uses many methods of the original nuclear research
work, originally developed mainly for basic research. In many laboratories the
RBS (Rutherford Back Scattering) is applied. The principle and one schematic
spectrum are shown in Fig. 11.21. Ions impinge with energy E o on the sample,
which is composed of the species A A and A B . After scattering they leave the sample
with energy E 1 and are than energy analyzed. A typical spectrum is shown in the
lower part of Fig. 11.21. According to the kinematics for each element an upper
energy is measured which indicate the elements on the surface of the sample. With
703
Fig. 11.20 Present and
future high energy
implantation [35]
The implantation can be used not only for elemental semiconductors, but also
for compound semiconductors as GaAs, InP or superlattices. Figure 11.20 shows
diagrammatically the whole field as dose dependent on ion energy [34]. To increase
the performance of high power devices high energy ion beam irradiation is also used
to reduce the charge carrier life time. In contracts to the common used life-time
killing with electron beams, the damage area of ions is concentrated at the Bragg
peak. This allows the reduction of the carrier concentration without a changing of
the main electrical specification of the device.
Accelerators used for that work are van de Graaff accelerators, dynamitrons and
in increasing number also RFQs. In all these types of accelerators the controllability
of the ion energy is one of the major advantages.
11.2.3.2 Analysis of Materials
The analysis of materials uses many methods of the original nuclear research
work, originally developed mainly for basic research. In many laboratories the
RBS (Rutherford Back Scattering) is applied. The principle and one schematic
spectrum are shown in Fig. 11.21. Ions impinge with energy E o on the sample,
which is composed of the species A A and A B . After scattering they leave the sample
with energy E 1 and are than energy analyzed. A typical spectrum is shown in the
lower part of Fig. 11.21. According to the kinematics for each element an upper
energy is measured which indicate the elements on the surface of the sample. With