Molybdenum News Center

The Effects of Sapphire Substrates Processes to The LED Efficiency

The GaN samples used in this work were grown using metal organic chemical vapor deposition (MOCVD) onto the c-plane sapphire substrates,the common structure of GaN-based LED is used. It consists of a low-temperature GaN buffer layer about 200um, then a 1um undoped GaN layer, a 2um conductive n-type GaN layer, a InGaN/GaN multiple-quantum-well (MQW) active layer, and about 0.5um p-type GaN layer on the top. A schematic process of the device making. Firstly, we make the chip-on-wafer by the common method, which include common GaN LEDs fabricating steps. Photolithograph and dry etching was performed in an Oxford Plasmalab 100 inductively coupled plasma (ICP) reactor to expose the n-type GaN, then standard lift-off process for Ni-Au (5nm/5nm) as p-GaN ohmic contact material, Ti/Al/Ti/Au as n-type ohmic contact by electron-beam evaporation.

After annealing, the Ni-Ag is deposited and lift-off as the pads to finish the making process of chip-on-wafer. Secondly, we grind and polish those wafers to 100um, 200um and 400um separately. After study of the thickness influence, the 200um samples are selected to make bottom texture samples. Parts of the samples are to just grind the bottom and make an irregular roughness bottom surface. Other parts of the samples are to make SiO2 mask on the bottom of wafer by the plasma enhanced chemical vapor deposition (PECVD). And then dry etching was performed in an Oxford Plasmalab 100 ICP reactor, in which the ICP source operated at power (1300W). At last the samples are scribed by laser scriber and flip-chip to the Si-submount to form the flip-chip LED. The luminance intensity is detected by the up-side photodetectors.


More molybdenum product: http://www.molybdenum.com.cn
Tel: 0592-5129696 Fax：0592-5129797
E-mail:  This email address is being protected from spambots. You need JavaScript enabled to view it.
Tungsten & Molybdenum Information Bank: http://i.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
Tungsten News & Tungsten Price: http://www.chinatungsten.com

• < Prev
• Next >