Capability

For more J.Kim’s lab tools information can be found here.

Wafer bonding technology offers significant advantages for synthesis of hetero-junctions that cannot be usefully synthesized by more familiar methods such as epitaxial growth techniques. Materials with large misfits or different lattice structures across interfaces can be bonded without causing defect formation in the crystals adjacent to the bonded interfaces. Our interface synthesis instrumentation design utilizes surface research techniques to measure and control substrate and interface chemistry within limits necessary to make hetero-junction devices. (See the details)

For the electrical characterization, a Cascade Summit series probe station  with integrated environmental control  capable of probing structures on wafers (up to 200 mm diameter) over a temperature range of -65 to 200 °C (Fig. 4) will be used.

The probe station provides for current measurement down to fA and capacitance measurement down to tens of fF.  A Lakeshore Cryogenic low temperature probe station which expands the accessible temperature range and permit device level characterization on structures down to temperatures of ~4.5K.  The facility has an Agilent 4155 semiconductor parameter analyzer, an Agilent 4284A LCR meter, an Agilent 81110A pulse/pattern generator, a Tektronix DP07104 digital oscilloscope, Keithley 4200 semiconductor parameter analyzers, a Keithley 590 capacitance-voltage meter and a variety of other electronics that are integrated with a low current switch matrix.  This equipment permits almost any device electrical test for MOS capacitors and transistors including current-voltage, capacitance and conductance as a function of voltage and frequency, pulsed current-voltage to characterize transient response, charge-pumping to measure dielectric/semiconductor interfacial defects, and automated reliability characterization for stressing a device while intermittently measuring any of the above electrical characteristics.  Fig. 5 illustrates MOS devices fabricated at UTD with good performance and intrinsic reliability.

A cryoelectronics laboratory has also been assembled consisting of four major equipment items: a superconducting cryostat and closed cycle crysostat for magneto spectroscopy.  The superconducting cryostat includes a Liquid helium dewar and homebuilt probes, a 50.8 mm Dia. superconducting solenoid (0 – 5 T, with persistent switch) and is capable of a measurement temperature range of 2.0 K to 300K.  The closed cycle cryostat for magneto spectroscopy is manufactured by Advanced Research Systems, Inc. and is a Displex™ Plus Closed Cycle System Model CSW-202+ with tail section for insertion in magnetic pole pieces.  The system has a cooling capacity of 50 mW at 4.2 K, and a highest operational temperature of 350 K and is mounted on electromagnet with moveable pole pieces (water cooled, 0 – 1.0 T). The laboratory also has a UV-visible monochromator (Newport C-130 UV/VIS 1/8 m Cornerstone) with a motorized scan range of 200 nm – 1600 nm.  There is also associated free space optics and a chopper detection system. A computer controlled  I – V electronic measurements and data recording system is also utilized based upon instrumentation manufactured by Keithley and HP.

For electrical measurements, we will fabricate capacitors and long channel transistors in this program. The Cleanroom Research Laboratory, located in the new Natural Science and Engineering Research Laboratory will be utilized to support this program.  The total area of this facility includes 5,000 sq. ft. of class 10,000 space.  This facility contains semiconductor processing tools including optical, e-beam, and nanoimprint lithography, chemical processing hoods, evaporation, sputter and chemical vapor deposition systems, as well as a wide variety of material and processing diagnostics.  The total tool count is currently at 70.  The facility is supported by an experienced staff of 3 professionals and 5 technicians.  The professional staff includes the cleanroom associate director, Mr. Wallace Martin, with more than 37 years of experience in semiconductor R&D.  Process engineering support is provided by Dr. Gordon Pollack and Dr. Roger Robbins with a combined 55 years of experience in semiconductor R&D.  All of the technician support staff members have extensive cleanroom operations and tool experience as well.

The lithography component in the cleanroom facility consists of a Quintel contact printer, a Karl Suss optical aligner with backside alignment capability, and a nanoimprint lithography tool.  The ability to make photomasks in-house allows us to make design changes quickly, and for the students to try new concepts with a minimal cost. A Heidelberg DWL66 Laser Lithography Tool permits the fabrication of up to 5” masks as well as direct write capability on wafers with .6 micron resolution.  A Quintel aligner is also available with a G-line contact printer with ~ 1 micron resolution and backside alignment capability (~1 micron).  It will accept up 150 mm wafers.  For nanoscale features, the direct write capability of the LEO SEM is utilized and described below.

Exposed resist is developed in 2 versatile “CPK” developers using spray and spin wet processes.  One CPK is configured to etch Chrome photomasks and caustic develop of positive photoresist. The other CPK unit is configured for solvent develop of negative photoresist. This technology is highly automated and contains up to 99 process programs.  These tools produce developed substrates nearly free of particles.

The thin-film deposition component of the lab includes a Uniaxis Plasma Enhanced CVD (up to 150 mm wafer), a CHA Mark 50 E-beam evaporator (3 guns with co-evaporation capability), two E-beam evaporators (each fitting up to 150 mm wafers), a Denton thermal evaporator, a new AJA four-head sputter deposition system (designed for 100 mm wafers) and a “Tystar” Low Pressure Chemical Vapor Deposition system.  The LPCVD tool is designed for either 100-150 mm wafers and has 4 tubes.  Deposition of low stress silicon nitride, polysilicon and silicon dioxide films is available.  For atomic layer deposition, a Cambridge NanoTech Savannah 200 ALD system is available.

Current plasma etch capability includes the following systems:  Oerlikon Versaline chlorine-based ICP etcher,  Oerlikon Versaline fluorine-based ICP etcher with DSE (deep Silicon etch) capability a “Technics” RIE for 100-125 mm wafers, a Plasmaline barrel asher/etcher, and a MARCH PX250 asher/etcher.

There are several anneal and oxidation furnaces available including a Tystar 4 tube atmospheric furnace configured for oxidation and dopant diffusion, 4 Minibrute tube furnaces (100mm), two MPT RTA systems, and a JetFirst 200 Rapid Thermal Anneal (RTA) system (up to 200 mm wafers).

The clean room diagnostics include, a spectroscopic ellipsometer, optical microscopes (Leica INM 200 and Leica INM 100),  ALESSI 4 point probe, and a high resolution AFM, a Thermoelectron FTIR with grazing attachments, a Nanometric Nanospec 6100 film thickness measurement system, a Veeco Dektak VIII profilometer and a Toho film stress measurement tool.  A new $1M Field emission SEM (Zeiss LEO Supra40) with e-beam writing capability, Zyvex nanomanipulator/prober, secondary, STEM, backscattering detectors, as well as EDAX is also available for students in this facility.

A complete list of tools can be found at here.