THE DESIGN AND APPLICATION OF ELECTRON-CYCLOTRON-RESONANCE DISCHARGES

During the past ten years electron cyclotron resonance (ECR) plasma-pr ocessing technology has matured into a diverse assortment of ECR plasm a reactor and plasma source design concepts and has been extensively a pplied to numerous low-pressure plasma processing applications, This p aper reviews the substantial progress made in the design and applicati on of ECR plasma technology in recent years. Five representative ECR r eactor/source designs from large-area 450-cm(2) discharges to compact plasma sources inserted into molecular-beam epitaxy (MBE) machines are described in detail, The performance of these ECR devices is evaluate d by computing performance figures of merit from the available experim ental data. These calculations are then compared with the behavior as predicted from a global model of the discharge. This comparison sugges ts that global plasma models can be employed as an approximate method for ECR reactor design. More extensive diagnostics and numerical model s that investigate the spatial variation of ion density and ion energy distributions are also presented. Several illustrative ECR plasma-pro cessing applications are discussed. These include submicron etching of silicon, etching of III-V and II-VI electronic and photonic devices, and the epitaxial growth of GaN, The variety and the sophistication of these applications demonstrate that low-pressure high-density ECR pla sma processing technology has evolved into a very useful, versatile gr oup of plasma-processing machines.