화학공학소재연구정보센터
Thin Solid Films, Vol.520, No.6, 2155-2157, 2012
Thermal stability of N-polar n-type Ohmic contact for GaN-based light emitting diode on Si substrate
Thermal stability of N-polar n-type Ohmic contact for GaN light emitting diode (LED) on Si substrate was investigated. Al/Ti/Au were deposited as the contacts on the N-polar n-type GaN with and without AIN buffer layer on the surface, respectively, and both contacts exhibited Ohmic behaviors. The samples with AIN showed excellent Ohmic contact thermal stability when annealed below 700 degrees C, while the samples without AIN experienced serious degradation on electrical properties after being annealed in the temperature range of 250-600 degrees C. After the process of aging at 30 mA (155 A/cm(2)) and room temperature for 1000 h, operating voltage increase less than 0.05 V for LEDs with AIN but more than 0.45 V for LEDs without AIN. Therefore, we conclude that the existence of AIN buffer layer is a key of forming high stable Ohmic contact for GaN-based vertical structure LED on Si substrate. (C) 2011 Elsevier B.V. All rights reserved.