Etching of indium phosphide materials for microelectronics fabrication

摘要

A method of etching of indium phosphide (InP) semiconductor materials using methyl chloride CH.sub.3 Cl and phosphine PH.sub.3 in a low pressure MOCVD reactor is provided. Etching of InP using CH.sub.3 Cl as an etchant and PH.sub.3 to prevent thermal decomposition of the etched surface gives excellent etching morphology, and a maximum etching rate of 0.75 mm/hr for the CH.sub.3 Cl flow rates studied. A PH.sub.3 flow rate. ltoreq.40 SCCM and etching temperature≧610° C. provided excellent etch morphology, without formation of pits, independent of the CH.sub.3 Cl flow rate. A controllable etching rate was obtained for a coated susceptor when deposits are primarily InP. Thus this method of CH. sub.3 Cl etching is suitable for multiple growth and etching steps using an MOCVD reactor. By controlling the PH.sub.3 flow for a coated susceptor, the etching rate as a function of distance from the leading edge of a wafer can be linearized, to provide for a uniform etch rate over the entire wafer when a rotating susceptor is used. Use of an in-situ CH.sub. 3 Cl etch reduces both the total and active amounts of contaminants seen at the regrowth interface. The uniform etching rate combined with the reduction in interface contamination is advantageous for CH.sub.3 Cl in etching in combination with MOCVD InP crystal growth.