Investigation of Strain of GaN Light-emitting Diode Films Transferred to Metal Substrate from Si (111)

GaN-based MQW light-emitting diode films was transferred to metal substrate from Si(111) substrate by electro-plating and chemical etching.Then,high resolution X-ray diffraction(HRXRD) and photoluminescence(PL) was used to investigate the strain of GaN films in the transfer process.In the study,we designed a series of metal substrates of different structure:(1) Copper substrate,(2) chrome substrate and (3) copper/nickel/copper substrate because of their special thermal and mechanical properties.It was revealed that the tensile strain of GaN films decreases when it is transferred from Si(111) substrate to such three kinds of metal substrates,which is propitious to GaN films.And there is a maximal decrease of tensile strain when GaN films are transferred to chrome substrate.The main layer of electro-plating chrome in the chrome substrate is playing an important role in the sustentation to GaN films.And it was found that,with the thickness increasing of main layer,the strain of GaN films has no change,so the thickness of main layer could be added as more as possible,which can enhance the mechanical properties of chips in the manufacture process.