Method for Enhancing Growth of Semipolar Nitride Devices

Brief Description

A method for enhancing the growth of semipolar nitride films using either a buffer layer or a nucleation layer. 

Background

GaN and its alloys (AlGaN, InGaN, AlInGaN) have been established as effective for fabrication of visible and ultraviolet optoelectronic devices and high-power electronic devices. These devices are most often grown along the polar c-direction, using a variety of growth techniques, including molecular beam epitaxy (MBE), metalorganic chemical vapor deposition (MOCVD), or hydride vapor phase epitaxy (HVPE). However, growing devices along the polar c-direction results in charge separation, spontaneous polarization, and degraded device performance. Growth of such devices along a semipolar axis could significantly improve their performance by eliminating the spontaneous and piezoelectric polarization that occurs. 

Description

UC Santa Barbara researchers have invented a method for enhancing the growth of semipolar nitride films using either a buffer layer or a nucleation layer. Samples can be grown onto substrates measuring two inches in diameter, whereas previous semipolar nitrides could only be grown on substrates a few micrometers wide. Films are grown using a commercially available MOCVD system, with a pressure range between 10 and 1000 torr, and a temperature range of 400-1400°C. These variable growth conditions demonstrate the stability of the growth of GaN using a suitable substrate. Growing these films on a semipolar surface reduces the polarization effects and built-in electric fields of III-nitride devices.   

Advantages

·         Large variability in pressure and temperature growth parameters

·         Ease of manufacturing and processing

·         Greater growth area of devices

Applications

·         LEDs

·         Laser diodes (LDs)

Patent Status