AbstractThis letter reports on multi-layer submicron epitaxial device structures grown by hydride vapor phase epitaxy (HVPE). This is the first demonstration of both high electron mobility transistor (HEMT) devices and ultraviolet light emitting diodes (LED) emitting in the wavelength range from 305 to 340 nm based on AlGaN/GaN and AlGaN/AlGaN heterostructures grown by HVPE. Two unique aspects of this technological approach are the growth of Al-containing epitaxial material by HVPE and use of HVPE to form submicron multi-layer epitaxial structures. The high performance of HVPE grown devices presented in this report demonstrates the significant potential that exists for HVPE growth technology for mass production of device epitaxial wafers.