Low Pressure Source for Mass-Selective, Diffusion Assisted Epitaxy

Award Information
Agency:
Department of Defense
Amount:
$99,994.00
Program:
STTR
Contract:
F49620-02-C-0061
Solitcitation Year:
N/A
Solicitation Number:
N/A
Branch:
Air Force
Award Year:
2002
Phase:
Phase I
Agency Tracking Number:
F023-0193
Solicitation Topic Code:
N/A
Small Business Information
Svt Assoc., Inc.
7620 Executive Drive, Eden Prairie, MN, 55344
Hubzone Owned:
N
Woman Owned:
N
Socially and Economically Disadvantaged:
N
Duns:
876868647
Principal Investigator
 Amir Dabiran
 MBE Lab Manager
 (952) 934-2100
 dabiran@svta.com
Business Contact
 Jane Marks
Title: Project Manager
Phone: (952) 934-2100
Email: marks@svta.com
Research Institution
 University of Minnesota
 Philip I Cohen
 Dept. of Elec. & Comp. Eng., 200 Union Street SE, Room 4-17
Minneapolis, MN, 55455
 (612) 625-5517
 Nonprofit college or university
Abstract
Dramatic differences in the diffusivities of the constituents of novel thin film materials and structures limit material perfection under far from equilibrium growth conditions. We will develop a new light-mass ion source, compatible with the low pressurerequirements of molecular beam epitaxy (MBE), to provide selective enhancement of the motion of surface atoms. Helium or hydrogen ions incident on a surface at approximately 100 eV will mainly transfer their energy to lower mass, surface atoms. Thislow-pressure ion source will be compared to a higher pressure Kaufman source for the MBE growth of technologically important III-nitride materials. The low-mass ions will overwhelmingly deposit their energy at the N atoms, effectively setting the growthconditions closer to equilibrium. The results will be compared to literature reports using higher mass ions. For low-mass ions incident at low angles with low energy, the energy transfer will be well below sputtering thresholds. The impinging ions willonly be able to excite local phonon modes that selectively enhance surface diffusion. If more momentum transfer is desired, higher mass ions could be used. Development of this new ion source would greatly impact a wide range of materials systems.Currently, the growth of multicomponent thin films and films with hyperabrupt interfaces challenges all growth techniques. The proposed low-mass ion source will allow control of defects, grain size, surface chemistry, and enable abrupt hetero-epitaxialcombinations not currently possible. As a proof of concept, the enhanced MBE growth of GaN and InGaN will be demonstrated. This technique would greatly benefit the development of novel semiconductor thin films and structures.

* information listed above is at the time of submission.

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