Diamond epitaxy and ALD dielectric layers for RF Devices

Project: Research project

Description

Arizona State University has advanced capabilities for diamond film growth and atomic layer deposition. Processes for epitaxial diamond film growth have been established in three different microwave plasma chemical vapor deposition (MPCVD) systems. The systems are individually optimized for n-type, p-type and intrinsic epitaxial layer growth. Prior to growth single crystal diamond substrates are cleaned with an acid etch. After loading into the MPCVD chamber the substrates are heated to the desired temperature using a combination of plasma induced heating and substrate heating. The surface is initially exposed to a hydrogen plasma for approximately 30 min to prepare the surface. This is followed by the growth step where methane and any dopants are admitted into the chamber. Cool down is in the hydrogen plasma and hydrogen to maintain the hydrogen surface termination. All surfaces are characterized with optical microscopy. Atomic force microscopy is also available. Electronic state characterization is available using UV and/or x-ray photoemission spectroscopy.

Atomic layer deposition of Al2O3, HfO2 and SiO2 are achieved in a custom remote plasma enhanced ALD (PEALD) system. The PEALD system is interconnected with a remote plasma surface preparation and hydrogen or ammonia plasmas are routinely employed prior to ALD deposition to obtain appropriate termination prior to PEALD dielectric layer growth. The PEALD uses appropriate metal-organic precursors and an oxygen plasma as the second reactant. Typical growth rates are 1.5 A/cycle and a cycle time of about 120 sec. The system is also connected to an XPS system which can be used to confirm ALD layer thicknesses up to a thickness of ~5 nm. Post deposition annealing is typically employed in a hydrogen/nitrogen environment. XPS is used to confirm characterize the bonding configurations in the film.

The project will provide a range of materials characterization options. SIMS can be employed on selected samples for doping and impurity content. Hall effect is now available for selected samples to determine the carrier type, density and mobility. In situ XPS and UPS will be employed for thickness measurements, bonding configurations, and electronic state characterization (band offsets and band bending).
StatusFinished
Effective start/end date12/1/149/30/19

Funding

  • US Department of Defense (DOD): $262,499.00

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epitaxy
diamonds
hydrogen plasma
atomic layer epitaxy
diamond films
hydrogen
chambers
vapor deposition
microwaves
cycles
heating
oxygen plasma
configurations
electronics
secondary ion mass spectrometry
Hall effect
ammonia
photoelectric emission
methane
atomic force microscopy