Negative resists resist

Both solvent-iaduced swelling and oxygen inhibition ate characteristic of all cross-linking negative resists based on free-radical chemistry. 

The impact on negative-CA resists of airborne base contamination differs qualitatively from their positive tone counterparts. Suppression of acid-catalyzed chemistry at the surface of a negative resist results in some film erosion at the top of the exposed fields and in some cases an apparent loss of photosensitivity, but in general the reUef images formed exhibit the expected cross-sectional profile. This is in sharp contrast with the typical behavior seen with positive-tone CA resists, where suppression of acid-catalyzed chemistry at the surface causes an insoluble surface skin. 

Typical positive temperature coefficient (PTC) device behavior for a doped polycrystaHine BaTiO thermistor is presented in Figure 4. At temperatures below - 100° C and above - 200° C the material shows the expected negative resistivity vs temperature associated with semiconductors as expressed by ... 

Fig. 3. Lithographic process using positive- and negative-resist systems. The element (a) is (b), exposed to uv radiation (c), developed and (d), the metal is...

Nevertheless, the appearance of regions with negative resistance is generally not typical for the coulomb staircase phenomenon. However, several articles reported similar features both theoretically (Beenakker 1991, Stone et al. 1992, Prigodin et al. 1993) and experimentally (Reed et al. 1988). 

The observed phenomena can be explained if we consider that different behaviors in the V-I characteristics of the same granule (staircase and negative resistance) are measured when different values of current are locked by the STM feedback. This fact implies, of course, that different tip-granule distances are attained in the two cases. By considering the structure as a two-barrier system, we can suggest that one barrier, namely, that between the... 

FIG. 31 I-Vcharacteristics with negative resistance obtained with CdS particles. 

As in the case of CdS granules, two types of V-I characteristics were registered, namely, one with negative resistance regions (Fig. 36) and the other with steplike behavior... 

FIG. 36 I-V characteristics with negative resistance obtained with PbS particles. 

When the locked current was small (0.5 nA), giving rise to a large barrier between the granule and the tip, staircase-like V-I characteristics were registered (Fig. 37). Instead, when the value of the locked current was higher (1 nA), characteristics with negative resistance occurred at constant-voltage steps (Fig. 36). 

The negative resistance effect is observed when anodic oxides are subjected to so-called electroforming (i.e., annealing in vacuum).93 Such a treatment removes the special features of the anodic oxides (asymmetry of conduction and electric strength, electret effect, etc.), and the negative resistance effect may be explained using the general approach developed for amorphous dielectrics.5... 

Negative resists generally exhibit high sensitivity but low contrast. For instp.ncin our laboratory, polymers containing thiirane groups / g v ere found to be extremely sensitive (o = 6 x 10 T C/cm2) to electron beam irradiation at a 20 kV... 

John A. Copeland and Stephen Knight, Applications Utilizing Bulk Negative Resistance F.A. Padovani, The Voltage-Current Characteristics of Metal-Semiconductor Contacts P.L. Hower, W.W. Hooper, B.R. Cairns, R.D. Fairman, and D.A. Tremere, The GaAs Field-Effect Transistor Marvin H. White, MOS Transistors... 

At higher overpotentials the second-order terms become important, and Eq. (6.9) is no longer valid. At very large overpotentials, when eorj > A, Eq. (6.8) even predicts a decrease of the current with increasing overpotential, i.e., a negative resistance. However, better versions of this theory to be presented in the following section do not show this behavior. 

The first resist used to fabricate solid-state devices was a negative resist based on cyclized poly(cis-1,4-isoprene) which is crosslinked using a photoactive bis-... 

Nonswelling Negative Resists Incorporating Chemical Amplification... 

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