B-doping

In order to investigate the spatial distribution of B atoms in a B-doped HOD film, Graham et al. [415] deposited a 4-pm thick B-doped diamond layer on an undoped HOD film of 30-pm thickness. The B-doped layer was deposited using CH4, H2, and B2H2, where B/C = 44 ppm in the source gas. The specimen was thinned from the HOD film side so that TEM and CL measurements could be done for the same position of the specimen. In the CL spectrum related with dislocations, there were two bands at 2.87 eV (431 nm) and 2.32 eV (535 nm) due to bound excitons. A comparison between the TEM image and the monochromatic CL images for 2.87 and 2.32 eV indicated that the B dopants were distributed uniformly within the film on the submicron level. Furthermore, the incorporation of B dopants created dislocations in the film. 

Material Carrier concentration (lO /cmh Hole mobility (cm /V-s) Activation energy (eV) Reference 

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Fig. 5. Bipolar transistor (a) schematic and (b) doping profiles of A, arsenic ion implanted into the silicon of the emitter ( -type) B, boron ion implanted into the silicon of the base (p-type) C, antimony ion implanted into the buried layer ( -type) and D, the epi layer...

Fig. 4. Effect of dopant additions on the resistivity versus temperature behavior of BaTiO PTCR ceramics. A, undoped B, doped with 0.134 mol % Cr ...

Figure 7 SIMS depth profile of Si implanted into a 1- im layer of Al on a silicon substrate for 6-keV O2 bombardment The substrate is B doped.

Chemical erosion can be suppressed by doping with substitutional elements such as boron. This is demonstrated in Fig. 14 [47] which shows data for undoped pyrolitic graphite and several grades of boron doped graphite. The mechanism responsible for this suppression may include the reduced chemical activity of the boronized material, as demonstrated by the increased oxidation resistance of B doped carbons [48] or the suppressed diffusion caused by the interstitial trapping at boron sites. 

Figure 9-23. Schematic diagram ol the EL processes in an electrochemical cell, reproduced from Ref. 1481. (a) Cell before applying a voltage, (b) doping opposite site as n- and p-lype, and (c) charge migration and radiative decay where Mu M2—electrodes O---oxidized (p lype doped) species . ..reduced (n-lype doped) species . ..electron-hole pair.

FIGURE 26.6 (a) p-doped conductive polymer in battery cell configuration (b) -doped... 

Figure 4.7. Boron scanned ion beam mass spectrometry (SIMS) image of a B-doped diamond specimen. The image is 430 pm in width, and the variation of B intensity from one grain to another is approximately a factor of 8. (Reproduced by permission of Professor J. W. Steeds.)...

Figure 4. Particle size distributions for the original and ground B-doped carbon from WUT.

For B-doped p-type samples of Si with an acceptor concentration nA of 8.5 x 1019 the 29Si NMR also showed a Knight shift of 33 ppm (both n-type and p-type Knight shifts were reported as unsigned, presumably positive, values see Sect. 3.4.2). Comparison with results for the n-type sample led to the conclusion that there was a nearly equal admixture of s-type wavefunction for the hole wave function near the top of the valence band. 

The discovery of superconductivity in heavily B-doped diamond, which produces p-type material, has provoked interest in using nB and 10B NMR for characterization. The nB static NMR at 4.2 K of heavily-doped diamond (2.8-8.7 x 1021 B/cm3) showed two unresolved peaks, the sharper of which was... 

Fig. 2. Spreading resistance profile of four B-doped samples of (100) Si hydrogenated at 122°C. The three higher resistivity samples were hydrogenated for one hour the lowest resistivity sample was treated for four hours. The resistivities were obtained from a calibration curve. Note the greater penetration depth of atomic hydrogen as the boron concentration decreases.

Heating the B-doped samples above 200°C in vacuum to dissociate the hydrogenated complex results in flat spreading resistance (Rs) at the original bulk value. A second exposure to Hj restores the increased Rs at the surface. These are crucial experiments that demonstrate that hydrogen is involved and that the process is reversible and reproducible. 

Fig. 3. Spreading resistance profiles for 10-0 cm, B-doped (100) Si hydrogenated as shown.

Fig. 6. Typical resistivity profiles of B-doped Si after four hours in atomic hydrogen at the indicated temperatures.

In B-doped a-Si H, the B atoms can be inactive for two reasons 1) the B atom may be surrounded by only three Si atoms (trigonal binding), or 2) it may be in a tetrahedral site but with a neutralizing H atom... 

Pankove et al. (1985) measured the room temperature IR absorption spectrum of B doped Si that was passivated in an H2 plasma and found a band at 1875 cm-1 (Fig. 2). From a comparison of the observed vibrational frequency with typical values for B—H and Si—H bonds, it was argued that the H was attached to a Si atom in the B—H complex. It was further... 

Fig. 2. IR absorption spectrum of hydrogen passivated, B-doped Si measured at room temperature. [Reprinted with permission from the American Institute of Physics, Pankove, J.I., et al., (1985). Appl. Phys. Lett. 46, 421.]...

Substitutional B in Si has a triply degenerate local mode that is observed in both IR absorption and Raman spectra. There are two naturally occur-ing isotopes, nB (82.2%) and 10B (18.8%), with distinct vibrational bands near 623 and 646 cm-1, respectively (Newman, 1969). Changes in the Raman spectrum of the B local mode upon passivation by H or D have been studied (Stutzmann, 1987 Stutzmann and Herrero, 1988a,b Herrero and Stutzmann, 1988a). Spectra are shown in Fig. 6 for samples of B doped Si that are unpassivated and passivated by H and D. Upon passivation, the vibrations due to isolated B are reduced in intensity and new features appear at 652 and 680 cm-1 independent of whether the B is complexed with Hor D. 

Fig. 17. Temperature dependence of the diffusion coefficient for different phosphorus (P) or boron (B) doping levels, as indicated (Street el al., 1987b). The undoped data is after Carlson and Magee (1978). 

Fig. 4.11 Time frames obtained by simulation of stress-strain tests on (a) N-doped SWCNTs, (b) B-doped SWCNTs and (c) N-doped single layer graphene.

Yu, S.-S. Zheng, W.-T., Effect of N/B doping on the electronic and field emission properties for carbon nanotubes, carbon nanocones, and graphene nanoribbons. Nanoscale 2010,2 1069-1082. 

We now turn to photoconductive and photodiode detectors, both of which are semiconductor devices. The difference is that in the photoconductive detector there is simply a slab of semiconductor material, normally intrinsic to minimize the detector dark current, though impurity doped materials (such as B doped Ge) can be used for special applications, whereas by contrast, the photodiode detector uses a doped semiconductor fabricated into a p-n junction. 

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