MRI: Development of A New High Temperature Source Metalorganic Chemical Vapor Deposition System (HTS-MOCVD) for Next Generation IIIA/B-Nitrides

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Abstract Title: Novel High Temperature Research Instrument to fabricate next generation semiconductors for Power Electronics for electric vehicles and future electric grid.Group III-Nitrides are semiconductors beyond silicon that enable unique electronic and optical devices for power chargers for laptops, cell phones and other consumer electronics, and the electronics for hybrid and electric vehicles (HEV’s). These semiconductors are also used to manufacture the green, blue, and white light emitting diodes (LED’s) for high efficiency lighting and displays for which the 2014 Nobel Prize in physics was awarded. The III-Nitride semiconductors are also at the core of ultraviolet LEDs for disinfection and air-water purification. These unique and important semiconductors materials are produced using a high temperature growth process called Metalorganic Chemical Vapor Deposition (MOCVD) that is carried out in a unique high temperature equipment to allow high quality crystalline materials with a very high purity. It has been proposed that the incorporation of transition metals, such as Titanium and Scandium can enhance the performance of these semiconductor materials for power electronics by increasing the piezoelectrically produced electrical charge by ~2-10 times. This higher charge can will enable higher current levels in HEV’s. The challenge here is to produce high quality materials, which in turn require even higher temperature growth and chemical processes, for which there are currently no commercial tools available. In this proposal, we will develop both the hardware tools, and the chemical processes, and measurement techniques required to demonstrate the potential for this new high temperature, high current, high voltage technology. This Track-I NSF MRI proposal aims to develop a New High Temperature Source-Metalorganic Chemical Vapor Deposition System (HTS-MOCVD) for depositing the emerging IIIB-Transition- Metal Nitrides (such as ScN), and conventional IIIA-Nitrides (GaN-AlN-InN) in a single growth reactor. The III-B nitrides have very high piezo-pyroelectric coefficients making them ideal for high performance sensors. Moreover, their heterojunctions with III-A nitrides can potentially yield power electronic and UVB-C optoelectronic devices with performance level well above those of current devices. Our system design will have several innovative features such as a new high temperature source design, and a new precursor injector design. This new injector design will in essence allow source injection like in conventional MOCVD reactors very close to the growth susceptor. This nclose injection mode, and the high temperature source, will enable increased precursor injection efficiency and thus growth rates for ScN compatible with those of AlxGa1-xN. The close to susceptor/substrate injection will also lead to a significant reduction in the adduct formation thereby simultaneously improving the growth quality with a growth rate much higher than conventional MOCVD systems. Thus, our unique system design will allow the growth of thicker buffer regions and the active regions (typically much thinner) of the device structures simultaneously in the same system. It will also be ideal for depositing AlxGa1-xN/AlySc1-yN heterojunctions and quantum wells to explore their properties. MOCVD systems with our high temperature source and the dual injector design are commercially not available.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.