Low-temperature annealing

Fig. 15. Excess carrier concentration in HgCdTe in a saturated Hg vapor as a function of temperature where the dashed line represents Hg vacancies. The extrinsic impurity concentration can be adjusted in the growth process from low 10 up to mid-10. Low temperature annealing reduces Hg vacancy...

For carbon steels, however, a full stress-relief heat treatment (580-620°C) has proved effective against stress-corrosion cracking by nitrates, caustic solutions, anhydrous ammonia, cyanides and carbonate solutions containing arsenite. For nitrates, even a low-temperature anneal at 350°C is effective, while for carbonate solution containing arsenite the stress-relief conditions have to be closely controlled for it to be effective . 

ZnO films for use as buffer layers in photovoltaic cells (see Chap. 9) have been chemically deposited from aqueous solutions of ZnS04 and ammonia [57]. The solution was heated to 65°C, and adherent, compact Zn(OH)2 + ZnO films were formed after one hour. Low-temperature annealing converted the hydroxide to oxide. The solution composition will be important in this deposition. On one hand, increased ammonia concentration will increase the pH and therefore the homogeneous Zn(OH)2 precipitation in solution. However, further increase in ammonia concentration will redissolve the hydroxide as the ammine complex. There will clearly be an optimum ammonia (and zinc) concentration where Zn(OH)2 does form, but slowly enough to prevent massive homogeneous precipitation. The use of ammonia in (hydr)oxide deposition derives, in part at least, from its gradual loss by evaporation if the system is not closed [58], Any open solution of an ammonia-complexed metal ion (which forms an insoluble hydroxide or hydrated oxide) should eventually precipitate the (hydr)oxide for this reason alone. 

Reverse Time Effect of Diffusion. Michel (51) observed two new effects associated with the low-temperature annealing of B-implanted layers (1) an... 

These results suggest that a non-linear (i.e. superlinear) p(T) is caused by a filamentary flow of the current in the chain layer through interchain bridges formed by a residual amount of 0(5). Breaking the interchain links (by low temperature annealing, for example) leads to an increase of the magnitude of p(T) oc T2 in the chain layer, and consequently to a higher (but linear) total resistivity which is dominated by the planes. 

IMPACT OF LOW-TEMPERATURE ANNEALS OF ELECTROPLATED COPPER FILMS ON COPPER CMP REMOVAL RATES... 

Figure 9 STM images (a-c) and marble models (d) of the Pt jSn(001 )-surface after low temperature annealing. a)Overview, scan width (IbOGA) ", U =0.6V, I(=l. OnA. b)( 104)-facet on the side of a pyramid near the top. Scan width (lOOA), U, =0.2V, I,= 1.0nA. c)( 102)-facet on the side of a pyramid near the base. Scan width (120A)", Uy=0.4V, I,= l.0nA. d)Marble models of the (104)-facet (left panel) and the (102)-facet (right panel). For better visibility the models correspond to a chemically ordered bulk (Pt atoms light grey, Sn atoms dark grey), whereas the real pyramids are substitutionally disordered in the bulk. The unit cells seen by STM are indicated. From Ref. [27].

Figure 11 Experimental (left panel) and schematic (right panel) RHEED pattern of the Pt3Sn(001)-surface after low temperature annealing. The main features are transmission spots lying on horizontal lines rather than Laue-circles. The Laue-circles are indicated in the schematic pattern. Electron energy is l2keV, direction of incidence is along [100]. From Ref. [27].

By carefully selecting the thermal and mechanical history of a material, it is possible to tailor a number of different features of that material. Low-temperature anneals can induce precipitate reactions that increase the yield stress. Cold working changes the dislocation density, and this too alters the yield stress. If the material... 

Figure 8. Schemes illustrating the dislocation structure of grain boundaries in CP Ti as-processed by HPT (a) and after low temperature annealing (b).

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