Nanostructure Materials & Devices Laboratory
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I. UHV Interconnected Growth & In-Situ Processing, & Characterization system  >>
UHV Interconnected Growth & In-Situ Processing, & Characterization system:

MBE Chamber:
The MBE chamber is the heart of the Integrated UHV interconnected system and is used for fabrication of advanced III-V (Ga, Al, In arsenides) epitaxical nanostructures (quantum well, wires, and dots) and state-of-art devices (lasers, photodetectors, modulators, transistors). A reflection high-energy electron diffraction (RHEED) system is integrated on to the chamber that allows in-situ diagnostics and real-time control on epitaxical growth. The chamber has standard Knudsen effusion cells for deposition of Ga, In, Al, and As. Si and Be K-cells are available for doping of the structures. Additionally, a water-cooled Arsenic valved cracker is installed on the chamber. Substrate temperature is measured using an IR pyrometer. A quadropole mass-analyzer is used to monitor the background gas species in the chamber. The combination of cryopump, ion pump, and titanium sublimation pump on the chamber achieves base pressure in the low E-10 torr range.

AFM-STM Chamber:
This chamber was the first system that integrates STM/AFM that is UHV connected to an extensive growth and processing system. A unique design consisting of suspended bellows achieves vibration isolation of this chamber from the rest of the system, a key engineering feat that has enabled us to achieve atomic-resolution on III-V surfaces. This chamber enables a morphological evolution studies that look at effects of various types of growth or processing while avoiding deleterious effects of ambient exposure. An illustrative example is our studies on the kinetic pathways of the InAs 3D island formation on GaAs (001).

Cleaning/Metallization/Dielectric Chamber:
This chamber has quite diverse capability resulting from three distinct equipment that are mounted: (1) An electron-beam deposition system that allows deposition of low vapor pressure materials such as W, Au, Si, fluorides, oxides etc., (2) a gas-source cell containing a high-temperature filament which is used for cracking of molecular gases, and (3) standard Knudsen cells for deposition of low-vapor pressure materials. The chamber also has RHEED analysis capability. In our most recent work, we have extensively used this chamber for semiconductor surface cleaning using atomic hydrogen with a low thermal budget.

FIB Chamber:
The chamber is equipped with a liquid Ga ion gun and a nozzle for reactive gas delivery. Nanoscale features can be fabricated using Ga ions by either purely physical sputtering or with sputtering assisted chemical etching. The chamber is capable of patterning semiconductor as well as dielectrics.

PECVD Chamber:
The chamber is used for deposition of SiO2 and Si3N4. These dielectrics are typically used either as a mask layer for further FIB patterning or as surface passivation layers.

ECR Chamber:
The chamber uses an ECR source for the generation of reactive ions. The gases connected to this chamber enable etching of III-arsenides, Si, SiO2, and Si3N4. The chamber has been designed so that spectroscopic ellipsometry (SE) measurements can be performed to monitor the processes in real-time.

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MBE Chamber
AFM-STM Chamber

/Dielectric Chamber

FIB Chamber connected with PECVD Chamber
ECR Chamber