Control of plasma induced fluorine damage in P-HEMT using InSb barrier layer

We investigated plasma induced fluorine damage in P-HEMT by C₂F₆/CHF₃ RIE and found that fluorine atoms penetrated to the channel layer. We also found these fluorine atoms were apt to stack on a strained interface, like Si-planar doped layer and hetero interfaces, by thermal annealing. Utilizing the properties of fluorine atoms, we improved a P-HEMT structure that had an ultra thin InSb strained barrier layer above the Si-planar doped layer. The InSb barrier layer effectively absorbed the intruded fluorine atoms in P-HEMT, and the degradation in the carrier density and mobility was suppressed much more than that of conventional P-HEMT structure.