The 81st JSAP Autumn Meeting, 2020

Presentation information

Oral presentation

3 Optics and Photonics » 3.13 Semiconductor optical devices

[9a-Z13-1~9] 3.13 Semiconductor optical devices

Wed. Sep 9, 2020 8:30 AM - 11:30 AM Z13

Shiro Uchida(Chiba Inst. of Tech.)

9:00 AM - 9:15 AM

[9a-Z13-3] The effect of TMAH treatment to designed green-micro LED

〇(DC)JEONGHWAN PARK1, Heajeong Cheong2, Yasuhisa Ushida2, Wentao Cai1, Yuta Furusawa2, Yuto Ando1, Yoshio Honda2, Hiroshi Amano2 (1.Nagoya Univ., 2.IMaSSS Nagoya Univ.)

Keywords:micro-LED, TMAH

Gallium Nitride (GaN)-based micro-LEDs (µLED) have been regarded as a promising candidate because of several advantages such as high brightness, power consumption, lift time, response time, operating temperature. In addition, the controllable size of μLED allows to realize a high-resolution display for virtual reality and augment reality. LED-based on GaN material has high-performance, however, the sidewall damage caused by plasma-based dry etching is a serious problem in μLED as LED size reduces to a few microns. To overcome the sidewall damage, potassium hydroxide (KOH) treated μLED has been reported.[1] However, KOH attacks m-plane GaN surface and unintended surface occurs which may cause deterioration of device properties.[2] Tetramethylammonium hydroxide (TMAH) having OH- same as KOH can lead to a stable etching process of GaN due to precise control of OH- and (CH3)4N+.[3]
Here, we report the effect of TMAH on μLED. We designed 50*50 µm2, 70*70 µm2 size LED structure that has a p-contact metal pad of 12*40 µm2, and 32*60 µm2 then compare samples with and without TMAH treatment. The mesa was made by ICP process based on Cl2 gas followed by a sample that was soaked by 25 wt% TMAH at 80 °C for 1hour. Contact metal pads of P and N-type were Ni/Au (20/200 nm) and Ti/Al/Ti/Au (20/100/30/200 nm), respectively. Figure 1 shows the properties of μLED through I-V, leakage current, which values were improved with TMAH treatment. For more detail, we will report at the conference.