Process-induced defects

A wide variety of process-induced defects in Si are passivated by reaction with atomic hydrogen. Examples of process steps in which electrically active defects may be introduced include reactive ion etching (RIE), sputter etching, laser annealing, ion implantation, thermal quenching and any form of irradiation with photons or particles wih energies above the threshold value for atomic displacement. In this section we will discuss the interaction of atomic hydrogen with the various defects introduced by these procedures. 

C. A. Desmond, C. E. Hunt, and S. N. Farrens, The effects of process-induced defects on the chemical selectivity of highly doped boron etch stops in silicon, J. Electrochem. Soc. 141, 178, 1994. 

F CROSS RELAXATION EXPERIMENTS AND PROCESS-INDUCED DEFECTS... 

Kawai, Adhesion of resist micropatterns during drying after water rinse, Jpn. J. Appl. Phys. 34, 1093 (1995) U. Okoroanyanwu, C. Pike, and H.J. Levinson, Process induced defects in sub 150 nm device patterning using 193 nm lithography, Proc. SPIE 3998, 277 (2000). 

The physical size of some of the process-induced defects is beyond the physical resolution and detection limits of the traditional optical inspection techniques. The way in which each of the patterning processes contributes to defectivity in ArF-lithography-based device manufacture is related to the constituent materials in the photoresist and to the interaction of the photoresist with the substrate or ARC. 

Guerdal Z, Tomasino AP, Biggers SB. Effects of processing induced defects on laminate response interlaminar tensile strength. SAMPE J 1991 27 3-49. 

A periodic arrangement of many epitaxially grown thin layers with lattice mismatch constitutes a strained-layer superlattice. An example of such a superlattice structure can be found in the vertical-cavity surface-emitting laser (VCSEL). As discussed by Choquette (2002) and Nurmikko and Han (2002), the control of layer thickness, elastic strain due to LAN to us mismatch, stress-driven crack formation and processing induced defects in the superlattice presents major scientific and technological challenges in the development of these devices. 

These observations were the basis for the proposal that polymers, like ionic crystals, exhibit shock-induced polarization due to mechanically induced defects which are forced into polar configurations with the large acceleration forces within the loading portion of the shock pulse. Such a process was termed a mechanically induced, bond-scission model [79G01] and is somewhat supported by independent observations of the propensity of polymers to be damaged by more conventional mechanical deformation processes. As in the ionic crystals, the mechanically induced, bond-scission model is an example of a catastrophic shock compression model. 

In a more general application, thermoluminescence is used to study mechanisms of defect annealing in crystals. Electron holes and traps, crystal defects, and color-centers are generated in crystals by isotope or X-ray irradiation at low temperatures. Thermoluminescent emission during the warmup can be interpreted in terms of the microenvironments around the various radiation induced defects and the dynamics of the annealing process (117-118). ... 

Ion implantation generates many dangling bonds that form centers for nonradiative recombination. These centers decrease the carrier lifetime and compete effectively with radiative transitions. However, after hydrogenation, since hydrogen ties dangling bonds, the luminescence process becomes more efficient. Furthermore, since the 1.0-eV emission is obtained even before hydrogen is introduced, the new radiative center may be formed due to residual hydrogen in the c-Si that combines with the implantation-induced defects. 

After thermalization, the defects begin to migrate, recombine, cluster, or precipitate provided the temperature is high enough to activate the motion of point defects. The various possible processes depend on defect concentration and their spatial distribution as well as on defect mobility and their interaction energies. As in non-metallic crystals, internal and external surfaces act as sinks for at least a part of the radiation induced defects in metals. 

V. Kirsanov, A. Suvorov and Yu. Trushin, Processes of Radiation-Induced Defect Production in Metals (Energoatomisdat, Moscow, 1985). 

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