METHOD OF MAKING OHMIC CONTACT TO ALGAN/GAN Russian patent published in 2019 - IPC H01L21/285 B82B3/00 

FIELD: electrical engineering.

SUBSTANCE: invention relates to the technology of ultrahigh-frequency (UHF) microelectronics, specifically to the technology of forming high-power GaN transistors and UHF monolithic integrated circuits (UHF MIC) based thereon and, in particular, to thermostable low-resistive ohmic contacts to AlGaN/GaN heterojunctions. Surface of the semiconductor silicon plate with epitaxial heterostructure AlGaN/GaN undergoes chemical purification with formation of a double-layer photoresistive mask with subsequent plasma-chemical etching of the recess (deposit) in the barrier layer based on AlGaN. Then one performs successive deposition of thin films of barrier-forming layer based on tantalum (Ta) with thickness of 5–100 nm, layer of conductor based on aluminum (Al) with thickness of 5–1,000 nm and upper protective layer on the basis of tantalum (Ta) with thickness of 5–1,000 nm. At that, deposition of conductor film is performed by electron-beam evaporation, and films of barrier-forming and protective layers – by magnetron sputtering in vacuum at residual pressure. Then double-layer photoresistive mask is removed with subsequent thermal treatment of contacts in inert atmosphere.

EFFECT: invention provides high thermal stability of electrical parameters of the ohmic contact based on the Ta/Al/Ta composition, as well as improved morphology of the surface of its contact pad.

5 cl, 2 dwg