Effect ofMesaSpacing ontheElectrical Properties ofMesa Isolation inHighElectron Mobility Transistor Structures

Thispaperreport effects ofvariation spacing ofmesaisolation onpHEMT substrate inordergetanoptimumisolated area.The multilayer pHEMT substrate wasusedasa substrate andwetetching techniques havebeen applied toformtheislands. Thecitric mixture usedisC2H807:H202:H20 withratio of4:1:1. Themesaspacing usedinthis study wasvaries at570,792and835,um. Theetchtimeforeach spacing wasfixed at3 minutes. Theelectrical effectof mesa isolation spacingwas characterized through current-voltage curve. It wasfoundthatthe570,ummesaspacing shows optimumcurrent valueformesaisolation. This indicated that570,ummesaspacing etchwith citric acidmixture of4:1:1 ratio for3minutes etchtimecanproduceoptimumcurrent for application ofpHEMT device.