Darryl Shima

Gas field ion source and liquid metal ion source charged particle material interaction study for semiconductor nanomachining applications

Semiconductor manufacturing technology nodes will evolve to the 22, 15, and 11 nm generations in the next few years. For semiconductor nanomachining applications, further beam spot size scaling is required beyond what is capable by present generation Ga+ focused ion beam technology. As a result, continued Ga+ beam scaling and/or alternative beam technology innovations will be required. In this work, several alternative ion beam technologies are explored and compared to Ga+ beam for key nanomachining and substrate interaction attributes. First, thorough Monte Carlo simulations were conducted with various ion species incident on silicon and copper. Additionally, silicon and copper substrates were experimentally exposed to ion beams of helium, neon, and gallium. These substrates were subsequently analyzed to determine the sputter yields and subsurface damage.

Probe current distribution characterization technique for focused ion beam

Focused ion beam technology continues to scale into the nano regime to keep pace with the scaling of semiconductor processes and biological science research. As the requirements for higher image resolution and machining precision increase, the necessity for comprehensive analysis and fine tuning of the ion beam profile is becoming increasingly important and more challenging. Older techniques such as edge resolution analysis or ion beam spot burns provide only a limited understanding of the ion beam probe current distribution. In this paper, the authors discuss a quantitative ion beam probe current distribution measurement technique. The principle of the approach will be discussed; modeling and empirical results of a gallium beam profile are presented in this paper.

Nanomachining with a focused neon beam: A preliminary investigation for semiconductor circuit editing and failure analysis

As the semiconductor device scaling trend continues, advancement in both focused ion beam source development and application innovations are needed to retain failure analysis and nanomachining application capabilities. In this work, a neon gas field ionization source was studied for its nanomachining properties. The authors have analyzed neon’s nanomachining precision at 10 and 20 keV on blank Cu and SiO2 thin films. Subsurface material amorphization from neon and its correlation with beam current distribution are characterized by TEM. In addition, some preliminary nanomachining work was performed on a 32 nm test chip and successfully demonstrated end-pointing on various device layers.

Electrical and microstructure analysis of nickel-based low-resistance ohmic contacts to n-GaSb

Ultra low resistance ohmic contacts are fabricated on n-GaSb grown by molecular beam epitaxy. Different doping concentrations and n-GaSb thicknesses are studied to understand the tunneling transport mechanism between the metal contacts and the semiconductor. Different contact metallization and anneal process windows are investigated to achieve optimal penetration depth of Au in GaSb for low resistances. The fabrication, electrical characterization, and microstructure analysis of the metal-semiconductor interfaces created during ohmic contact formation are discussed. The characterization techniques include cross-sectional transmission electron microscopy and energy dispersive spectroscopy. Specific transfer resistances down to 0.1 Ω mm and specific contact resistances of 1 × 10−6 Ω cm2 are observed.

Mechanism and applications of helium transmission milling in thin membranes

Focused ion beam interaction profiles and nanomachining mechanisms are very different for membrane and bulk samples. In this work, a detailed empirical study was carried out to understand these differences by observing the progression of helium ion milling in silicon single crystalline membranes and bulk samples using cross-sectional transmission electron microscopy. The components of backward sputter yield and forward sputter yield unique to the membrane samples were observed, analyzed, and contrasted with the bulk sample sputter yield.

Controlled Growth of Ordered III-Nitride Core–Shell Nanostructure Arrays for Visible Optoelectronic Devices

We demonstrate the growth of ordered arrays of nonpolar

Low homologous temperature (<0.2) sputtering of indium films on silicon

\{ 10\bar{1}0\}

Growth and Optimization of 2-μm InGaSb/AlGaSb Quantum-Well-Based VECSELs on GaAs/AlGaAs DBRs

{101¯0} core–shell nanowalls and semipolar