198
7 Electronic Defect States
Fig. 7.18 Hole density in p-type silicon (N A = 7.4 × 10 14 cm −3 , E b
A = 46 meV (probably boron) and partial compensation with N D = 1.0 × 10 11 cm −3 ). Adapted from [609]
Fig. 7.19 Carrier concentration and conductivity type (red circles: p, blue squares: n) for MOVPE-grown
In x Ga 1−x As 1−y N y layers on GaAs (001) (layer thickness ≈ 1 µm, x ≈ 5%, y ≈ 1.6%) doped with different amounts
of silicon. The ordinate is the ratio of the partial pressures of disilane and the group-III precursors (TMIn and TMGa) in
the gas phase entering the MOVPE reactor. Lines are guides to the eye. Experimental data from [610]
An experimental example is shown in Fig. 7.18 for partially compensated p-Si (with N D N A ).
The change of slope around p ≈ N D is obvious.
If donors are added to a p-type semiconductor, first the semiconductor remains p-conducting as
long as N D N A . If the donor concentration becomes larger than the acceptor concentration, the
conductivity type switches from p- to n-conduction. If the impurities are exhausted at room temperature, the lowest carrier concentration is reached for N D = N A . Such a scenario is shown for p-type
In x Ga 1−x As 1−y N y doped with various concentrations of Si in Fig. 7.19. At high Si incorporation, the
number of charge carriers saturates due to autocompensation (see Sect. 7.5.5) and the formation of Si
precipitates. Since the ionization energies of donors and acceptors are typically different, the situation
for N D ≈ N A needs, in general, to be investigated carefully and will depend on the temperature.
7 Electronic Defect States
Fig. 7.18 Hole density in p-type silicon (N A = 7.4 × 10 14 cm −3 , E b
A = 46 meV (probably boron) and partial compensation with N D = 1.0 × 10 11 cm −3 ). Adapted from [609]
Fig. 7.19 Carrier concentration and conductivity type (red circles: p, blue squares: n) for MOVPE-grown
In x Ga 1−x As 1−y N y layers on GaAs (001) (layer thickness ≈ 1 µm, x ≈ 5%, y ≈ 1.6%) doped with different amounts
of silicon. The ordinate is the ratio of the partial pressures of disilane and the group-III precursors (TMIn and TMGa) in
the gas phase entering the MOVPE reactor. Lines are guides to the eye. Experimental data from [610]
An experimental example is shown in Fig. 7.18 for partially compensated p-Si (with N D N A ).
The change of slope around p ≈ N D is obvious.
If donors are added to a p-type semiconductor, first the semiconductor remains p-conducting as
long as N D N A . If the donor concentration becomes larger than the acceptor concentration, the
conductivity type switches from p- to n-conduction. If the impurities are exhausted at room temperature, the lowest carrier concentration is reached for N D = N A . Such a scenario is shown for p-type
In x Ga 1−x As 1−y N y doped with various concentrations of Si in Fig. 7.19. At high Si incorporation, the
number of charge carriers saturates due to autocompensation (see Sect. 7.5.5) and the formation of Si
precipitates. Since the ionization energies of donors and acceptors are typically different, the situation
for N D ≈ N A needs, in general, to be investigated carefully and will depend on the temperature.