We calculate the exact values of the holomorphic observables of N = 4 supersymmetric SU(N) Yang-Mills theory deformed by mass terms which preserve N = 1 SUSY. These include the chiral condensates in each massive vacuum of the theory as well as the central charge which determines the tension of BPS saturated domain walls interpolating between these vacua. Several unexpected features emerge in the large-N limit, including anomalous modular properties under an SL(2, Z) duality group which acts on a complexification of the 't Hooft coupling λ = g 2 N/4π.

Surface damage induced by reactive ion etching (RE) of SiN/SiO, stack used in the field isolation process was investigated in terms of its depth distribution and its correlation with junction leakage current. High leakage current is observed when oxidation induced stacking faults (OSF) are generated near bird's beaks in active regions from the Carbonrich surface damage induced by so called stop-on-Si RIE prior to the field oxidation process. Control of both OSF and the junction leakage current at lower levels is made possible if the C-rich surface damage is eliminated either by chemical dry etching (CDE) treatment of the surface or by use of RIE conditions with lower ion energies. INTRODU~TIONLOCOS (LOCal Oxidation of Silicon) continues to be one of the dominant isolation approaches owing to its relative process simplicity. To achieve device isolation width in the submicron range, however, the bird's beak of the field oxide into the active device regions niust be reduced. In principle, the reduction of the bird's beak can be realized using a SiN/SiO,/Si-substrate structure made of thinner strain-relief SiO,. As the thickness of the strain-relief SiO, is reduced, however, it becomes more difficult to terminate the reactive ion etching (ME) of SiN at the SiNISiO, interface due to the limitation of the etching selectivity of SiN against SO,.As altemative to the stop-on-oxide scheme mentioned above, an RIE scheme to be called stop-on-Si should be employed for patteming SiNISiO, stack in the field isolation process. In this stop-on-Si H E , Si substrate is directly exposed to plasma during the over etch step, thus suffers lattice damage from impinging ions during HE. For example, Kurosawa et al. reported that junction leakage occurred when the stop-on-Si RIIE of SiNISiO, stack and subsequent field oxidation were applied in the field isolation process and that the source of leakage was arising from oxidation induced stacking faults (OSF) in field regions'. Also, surface damage and contamination features were investigated by various methods such as transmission electron microscopy (TEM)*, Rutherford backscattering (RBS)3, and Auger electron spectroscopy ( A E S )~.In this paper, we have investigated the depth distribution of RIE-induced surface damage in the stop-on-Si scheme where well-controlled chemical dry etching (CDE) technique was utilized to profile the damage distribution.Thermal-wave (TW) measurement5 and reflection high energy electron diffraction (RHEED), and AES were used to examine nature of the RIE-induced damage. Further, we measured junction leakage current as a function of CDE depth to reveal a correlation between the REinduced surface damage before field oxidation and the resulting leakage characteristics in active regions. Based on these results, we propose a leakage current model in which the surface damage induced by the stop-on-Si RTE leads to leakage-generating OSF near bird's beaks after the field oxidation. EXPERIMENTALThe substrates used in this study were P-doped Si (100) wafers of 150" diame...

Solid-state reactions of titanium thin films on Si surfaces damaged and amorphized by CHF3/O2 plasma treatment were investigated. The formation temperature of the C49–TiSi2 phase increased due to plasma-induced damage and contamination from decomposed gas elements. The presence of a plasma-induced damage layer suppressed the interdiffusion of Ti and Si. The Ti5Si3 phase was formed initially at an annealing temperature of 400 °C when a plasma-induced damage layer was present at the interface. The increase of the C49–TiSi2 formation temperature may be caused by the transformation of the Ti5Si3 phase into C49–TiSi2 rather than by the direct nucleation of the C49–TiSi2 phase with a clean interface.

Side-wall damage in a transmission electron microscopy specimen of crystalline Si prepared by focused ion beam etching Low damage dry etching of III-V materials for heterojunction bipolar transistor applications using a chlorinated inductively coupled plasma Surface damage induced by reactive ion etching ͑RIE͒ was investigated in terms of its depth, distribution, and correlation with dislocation generation due to subsequent oxidation. Damage structure was evaluated using transmission electron microscopy, reflection high energy electron diffraction ͑RHEED͒, Auger electron spectroscopy, and thermal wave measurement technique. A chemical dry etching and surface analyze technique of RHEED and TW were utilized to profile the damage distribution. It is identified that the surface damaged layer consists of two parts; the upper part from the surface to about 4 nm is a heavily damaged amorphous structure containing carbon and the lower part, between 5 and 30 nm, is a single crystal Si with a lot of lattice defects. It is found that RIE damage may form film edge dislocations by the interaction of subsequent selective oxidation even though damage was minimized to suppress oxidation induced stacking faults generation. High leakage current occurs when n ϩ -p junctions are fabricated on this RIE and selective oxidation because of these film edge dislocations. It seems that generation of film edge dislocations has correlated with this carbon contained amorphous layer.

s h i h i r o Todokoro, Member Kyoto Research L a b o r a t o r y , M a t s u s h i t a E l e c t r o n i c s C o r p o r a t i o n , Kyoto, Japan 601