There are many techniques for achieving low dielectric materials. These materials can be deposited on the substrate either by spin-on or by chemical vapor deposition (CVD). Spin-on materials have several advantages different from those of CVDs, such as better gap filling capability, better planarization, lower cost, and easier use. The most studied low-k materials are fluorinated SiO 2 and inorganic spin-on-glass (SOG). Fluorinated SiO 2 has a dielectric constant of 3.1, but it does not meet the need of subquarter micrometer technologies. Inorganic SOG contains much silanol (Si-OH), and tends to crack due to large shrinkage during curing steps. 1,2 The organic SOP results in several beneficial film properties, e.g., low dielectric constant, decreased silanol content low moisture absorption, increased crack resistance, and excellent planarization.Currently, Cu and spin-on organic polymer (SOP) are the leading candidates for metal and dielectric materials. Device integration with lower dielectric constant material and lower resistance Cu film is capable of improving its performance and reducing the interconnection delay. [3][4][5] The major drawback of the next generation of Cu interconnects is the fast diffusion speed in the traditional oxide layer and in the low dielectric constant materials. 6,7 A thin barrier metal is inserted between the Cu and the dielectric layer, which is a conventional method for blocking Cu diffusion. This barrier metal-free structure 6,8,9 for SiON interlevel dielectrics has been proved to be an effective block for Cu diffusion and reduction of resistance-capacitance (RC) delay time. The other problem with organic SOP materials is the oxygen plasma stripping photoresist process, 10,11 which causes significant damage to organic low dielectric material, thus limiting its interlevel dielectric application. NH 3 plasma treatment can effectively improve the barrier effect against Cu and the ashing resistance at the same time. This method brought many good results with the exception of a little higher dielectric constant and leakage current than as-cured samples.In this study, a carbon-containing silicon nitride was achieved by NH 3 plasma exposed to organic SOP film. This layer has shown a much greater improvement in the barrier effect and in ashing resistance.Experimental The organic SOP (Allied Signals X-720) was spun on (100) 4-7 ⍀ cm p-type Si wafers. It is based on methyl(CH 3 ) phenyl(C 6 H 5 ) silsesquioxane. The thickness of SOP is approximate 200 nm after curing at 400ЊC for 60 min. The process steps used in this study are 1. A 200 nm SOP was spun on Si substrate. 2. SOP was treated with NH 3 plasma by plasma-enhanced chemical vapor deposition (PECVD) technique. The substrate temperature is 300ЊC, the pressure is 40 Pa, the flow rate of both NH 3 and H 2 is 300 sccm, and the rf power is 300 W.3. The ashing treatment was performed by a barrel reactor asher with oxygen plasma. The pressure is 0.5 Torr, the rf power is 100 W, the rf frequency is 13.56 MHz, and the exposure time is 10 mi...

Hydrogen silsesquioxane, a material with low dielectric constant, can successfully suppress Cu diffusion without using a barrier metal by implementing a NH3 plasma treatment. Lower leakage current and better barrier capability can be achieved by hydrogen silsesquioxane film after NH3 plasma treatment. Having been treated with different plasma exposure times, this film can still maintain its original dielectric constant with few changes. The decrease in leakage current with increasing exposure time can be attributed to the following mechanisms: dielectric film becomes denser, dangling bonds are passivated, nitride film is formed on the hydrogen silsesquioxane, and the bulk damage of hydrogen silsesquioxane is annealed out. A thin layer of nitride formed on the dielectric is the cause for having better capability. The thickness of the nitride layer on hydrogen silsesquioxane is about 35 nm, and it can prevent the Cu diffusion/migration into the underlying dielectric. The role of our nitride film is to act as a passive diffusion barrier. © 2000 The Electrochemical Society. All rights reserved.

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We describe the fabrication and electrical characteristics of single-wall carbon-nanotubes field-effect transistors (CNT-FETs) with a non-volatile memory function using ferroelectric thin films as gate insulators. The ferroelectric-gate CNT-FETs were fabricated using single-wall CNTs synthesized from alcohol by catalytic chemical vapor deposition and sol-gel derived PbZr 0:5 Ti 0:5 O 3 thin films. The ferroelectric-gate CNT-FETs showed modulation of the drain current with the gate voltage and the threshold voltage shift (memory window) on the drain current-gate voltage characteristics. Moreover, the memory window was saturated around 1.1 V as the gate voltage sweeping range increased. These results indicate that carriers in CNTs are controlled by spontaneous polarization of the ferroelectric films. Because ferroelectrics exhibit complex couplings between their electrical, structural, mechanical, thermal, and optical properties, and because CNTs have unique mechanical and electrical properties, ferroelectric-gate CNT-FETs offer promise as potentially useful nanoelectronics devices not only for non-volatile memory elements but also for high-sensitivity sensors.

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