Final report on LDRD project : outstanding challenges for AlGaInN MOCVD. Page: 3 of 44
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Printed March 2005
Final Report on LDRD Project: Outstanding
Challenges for AIGaInN MOCVD
J.R. Creighton, D.D. Koleske, G.T. Wang, M. E. Coltrin, A.A. Allerman, M.J. Russell, K.C.
Cross, C.C. Mitchell
Advanced Materials Sciences Department
S. R. Lee
Semiconductor Material & Device Sciences Department
D. M. Follstaedt
Radiation-Solid Interactions Department
Sandia National Laboratories
P.O. Box 5800
Albuquerque, NM 87185-0601
The AlGaInN material system is used for virtually all advanced solid state lighting and short
wavelength optoelectronic devices. Although metal-organic chemical vapor deposition
(MOCVD) has proven to be the workhorse deposition technique, several outstanding scientific
and technical challenges remain, which hinder progress and keep RD&A costs high. The three
most significant MOCVD challenges are:
(1) Accurate temperature measurement.
(2) Reliable and reproducible p-doping (Mg).
(3) Low dislocation density GaN material.
To address challenge (1) we designed and tested (on reactor mockup) a multiwafer, dual
wavelength, emissivity-correcting pyrometer (ECP) for AlGaInN MOCVD. This system
simultaneously measures the reflectance (at 405 and 550 nm) and emissivity-corrected
temperature for each individual wafer, with the platen signal entirely rejected. To address
challenge (2) we measured the MgCp2 + NH3 adduct condensation phase diagram from 65-
115 C, at typical MOCVD concentrations. Results indicate that it requires temperatures of 80-
100 C in order to prevent MgCp2 + NH3 adduct condensation. Modification and testing of our
research reactor will not be complete until FY2005. A new commercial Veeco reactor was
installed in early FY2004, and after qualification growth experiments were conducted to improve
the GaN quality using a delayed recovery technique, which addresses challenge (3). Using a
delayed recovery technique, the dislocation densities determined from x-ray diffraction were
reduced from 2x109 cm 2 to 4x108 cm 2. We have also developed a model to simulate reflectance
waveforms for GaN growth on sapphire.
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Mitchell, Christine Charlotte; Follstaedt, David Martin; Russell, Michael J.; Cross, Karen Charlene; Wang, George T.; Creighton, James Randall et al. Final report on LDRD project : outstanding challenges for AlGaInN MOCVD., report, March 1, 2005; United States. (digital.library.unt.edu/ark:/67531/metadc899542/m1/3/: accessed October 20, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.