Plasmachemical and wet etching in the postgrowth technology of solar cells based on the GaInP/GaInAs/Ge heterostructure

Investigation and development of a separating mesa-structure creating technology for fabricating multi-junction solar cells based on the GaInP/GaInAs/Ge heterostructure has been carried out. Studied were methods of etching of heterostructure layers: liquid chemical etching in the etchants based on HBr, K$_{2}$Cr$_{2}$O$_{7}$, H$_{2}$O and plasma-chemical etching in the stream of operating gas BCl$_3$. The comparative analysis of etching methods was studied. The protective masks based on photoresist layer and TiO$_{x}$/SiO$_{2}$ were developed. Multi-junction solar cells with low parameters of leakage current less than 10$^{-7}$ A at voltage 0,5–1 V were created.