AVS 45th International Symposium
    Electronic Materials and Processing Division Thursday Sessions
       Session EM-ThM

Paper EM-ThM5
Low Induced Damages Dry Etching of III-V Materials for HBT Applications using ICP in Chlorinated Plasma

Thursday, November 5, 1998, 9:40 am, Room 316

Session: Compound Semiconductor Surface Chemistry
Presenter: J.J. Etrillard, CNET, France Telecom
Authors: J.J. Etrillard, CNET, France Telecom
J.F. Bresse, CNET, France Telecom
C. Daguet, CNET, France Telecom
M. Riet, CNET, France Telecom
J. Mba, CNET, France Telecom
Correspondent: Click to Email
Etching of InGaAs and InP in ICP using SiCl4 was studied for HBT application. Low sample temperature was used to minimize the etching isotropy and to reduce the element V desorption. The low ion energy etching process results in a damaged layer thickness of a few angströms. AES results on InP demonstrate a very thin layer of non-stoichiometric material. The nature of the etching mask impacts on the surface contamination: local contamination effects due to sputtering are observed. For such low ion energy processes, the sample preparation before ICP etching is shown to be very important for the surface roughness, as observed by AFM. Various preparation shemes have been investigated, before ICP etching, aiming at a reduction of the surface degradation resulting from ICP etching. It is shown that the best results in terms of roughness and etch-rate are obtained with a silicon nitride mask and a surface oxidation before a wet desoxidation immediatly preceding the ICP etching. An ICP process was used successfully for partly etching the base mesa of HBT structures. No significant difference was observed in terms of induced damages and HBT current gain.