Enhance Algan/Gan Hemts Electrical Performance by Using Patterned Sapphire Substrate

As the market for personal communications services, and fifth generation (5G) mobile systems coming closer to reality, high frequency and high power device, radio frequency (RF) and microwave power amplifiers are beginning to be the focus of attention. However, the material properties of the commercial silicon process have gradually failed to meet this demand. To find the substitute materials becomes important issue. AlGaN/GaN heterojunction own large critical electric field and high electron mobility because of wide bandgap and 2DEG. Therefore, we can apply it to manufacturing high-power and high-frequency device. Currently, GaN has great opportunity for replacing Si. In this study, we primarily utilize patterned sapphire substrate (PSS) technology to epitaxy high-quality GaN by MOCVD and fabricate AlGaN/GaN HEMTs. We confirm that patterned sapphire substrate (PSS) technology indeed improve epitaxy quality by Raman analysis and EPD method. Moreover, we also design different etching depth to obtain different defect density material and find correlation between defect density and device performance. We successfully reduce etching pits density from 1.06x10(7)(cm(-2)) to 2.52x10(6)(cm(-2)) and FWHM of Raman spectrum from 2.34(cm(-1)) to 2.25(cm(-1)) by utilizing patterned sapphire substrate (PSS) technology. At the same time, we enhance the maximum drain current (I-DS, max) from 308(mA/mm) to 469(mA/mm), reduce on-resistance (R-on) from 16.4(Omega-mm) to 5.6(Omega-mm), and increase transconductance from 73.8(mS/mm) to 115.3(mS/mm).