Cl_2based dry etching of the AlGaInN system in inductively coupled plasmas

摘要

Cl_2-based Inductively Coupled Plams with low additional dc self-biases( - 100V) produce convenient etch rates(500-1500A min~(-1)) for GaN, AlN, InN, InalN and InGaN. A systematic study of the effects of additive gas(Ar, N_2, H_2,), discharge composition and ICP source power and chuck power on ethc rate and surface morphology has been performed. The general trends are to go theorugh a maximum in etch rate with percent Cl_2 in the discharge for all three mixtures, and to have an increase(decrease) in etch rate with source power(pressure). Since the etching is strongly ion-assisted, anisotropic pattern transfer is readily achieved. Maximum etch selectivityes of approximately 6 for InN over the other nitrides were obtained.