THIN FILM DEPOSITION

Services and costs


TECHNIQUES

Technobiochip Langmuir-Blodgett(LB) and Langmuir-Shaeffer(LS) deposition techniques far several years. These techniques allow to deposit ordered organic monolayers. The formation of an ordered molecular monolayer marks a great improvement in both chemical and biomolecular sensoristics, as the preferential orientation of the “active sites” of deposited molecules, leads to an improvement in terms of signal following the analyte-sensor interaction.


-Treatable substrates:

by using the LB/LS techniques is possible to deposit organic molecules onto several substrates, such as:

  • Metals: gold, platinum, titanium, etc.
  • Metal oxides: silicon or titanium oxides, etc.
  • Quartz: bare, or silanised in order to have surface specific groups.
  • Metal nitrides: silicon or titanium nitrides, etc.
  • Glass : cleaned, or silanised in order to have surface specific groups.



LB-LS DEPOSITION EXAMPLES

A) Example of organic deposition onto substrate for CHEMICAL SENSORS

LB-LS techniques have a wide application in chemical sensors, by means of active layers deposition onto transductors. A deposition of ordered layers of metallo-porphyrine (Mn-porphyrine) onto a 20 MHz quartz as nano-gravimetric sensor is thereinafter described. Firstly, a compression isotherm is calculated for the manganese-tetraporphyrine (Mn(L)TPP) (Fig. 1).



Figure 1: Mn(L)TPP compression isotherm
A target tension of 30 mN/m has been calculated from the compression isotherm. The next step was to deposit the requested number of layers for surface modification.


B) Example of organic deposition onto substrate for BIOLOGICAL SENSORS

An example of a deposition of anti-IgG mouse antibody molecules by LB method onto titanium/titanium oxide electrodes is here reported (Fig. 2). After defining the target tension at which the deposition isotherm could be performed, a certain number of anti-IgG layers has been deposited for surface modification of sensors (Fig. 2).



Figure 2: anti-IgG deposition isotherm (A) and target surface tension(B)


C) Example of organic deposition onto substrate for GENERAL PURPOSE

The third example is the deposition by means of LB-LS techniques of poli-methylmetacrilate (PMMA) films, in which the meta-methylmetacrilate polimerization in the presence of a photoresist makes holes that are ten nanometer wide, thus increasing the contact surface.
First of all, the compression isotherm of the meta-methylmetacrilate monomer was calculated (Fig. 3).

Figure 3: meta-methylmetacrilate compression isotherm


After that, by using as sub-phase an ammonium persulphate solution (NH4S2O8), that catalyzes the meta-methylmetacrilate polimerization, a number of layers of polymers were deposited by using the LS technique. The presence of a photoresist produced the holes formation inside the polimeric surface (Fig. 4).



Figure 4: Assing STM microscope unmodified (left) and PMMA-modified silicon substrate (right) acquisitions (kindly performed at the NRC-MSI, Rome). The signal intensity graduation on the right indicates the dimensions of particles expressed in nm.





SERVICES AND COSTS


DEPOSITION COSTS

LB-LS deposition cost essentially are determined by three variables:

  • Number of layers to be deposited
  • Substrate dimension
  • Velocità di trasferimento delle molecole (nel caso della tecnica Langmuir-Blodgett).

Thereinafter, a table of costs per layer for 5 substrates is reported (Table1).

KSV 5000 available depositions

Price/layer
(≤10layers)

Price/layer
(≤20layers)

Price/layer
(>20layers)

70 €

65 €

60 €

50 €

45 €

40 €

45 €

40 €

35 €

Table 1: prices of the different type of depositions. x, y e z depositions are possible by Langmuir-Blodgett method; while by Langmuir-Shaeffer is possible the type y only.


A report will be enclosed together with the LB or LS modified substrates, in which the compression isotherms and graphs are reported; moreover, as far LB method, deposition isotherm and transfer percentage of the organic compound onto substrate will be available.