公开(公告)号：US3859178A

公开(公告)日：1975-01-07

申请号：US43428674

申请日：1974-01-17

Applicant: BELL TELEPHONE LABOR INC

Inventor： LOGAN RALPH ANDRE ,  MILLER BARRY IRWIN

IPC: C25D11/32 ,  H01S5/227 ,  C23B5/48 ,  C23B5/46 ,  C23B9/00

CPC classification number: H01S5/227 ,  C25D11/32 ,  H01S5/2275 ,  Y10S148/051 ,  Y10S148/056 ,  Y10S148/072 ,  Y10S148/106 ,  Y10S148/107 ,  Y10S148/117 ,  Y10S148/118 ,  Y10S148/145

Abstract: A multiple anodization technique is described for producing GaAs layers of nonuniform thickness; that is, GaAs layers having substantially rectangular steps or grooves of the type capable of guiding light. The technique includes the following steps: (1) growing a native oxide layer on a major surface of the GaAs layer by submersing the GaAs layer in an anodization bath of concentrated H2O2 having a pH less than 6; (2) removing selected portions of the oxide layer so as to expose the GaAs layer adjacent to the desired step region; and (3) immersing the surface again in an anodization bath of concentrated H2O2 having a pH less than 6. Also described are techniques for growing by liquid phase epitaxy an AlGaAs layer over the resultant GaAs step structure in a manner which alleviates two problems: the formation of deleterious oxides on the GaAs layer and the dissolving of the step configuration while in contact with the AlGaAs growth solution.