It is shown that the In-Ga-P melt which is prepared by contacting with the GaP seed becomes supersaturated in reality. Some peculiarities of In,Gal -,P/GaAs films formation at quasi-equilibrium conditions are described. It is observed that the saturated In-Ga-P melt dissolves the GaAs substrate when isothermally contacting if the In,Gal -,P equilibrium solid has the lattice parameter less than that of GaAs. As a result some InGaAsP deposit arises on the substrate. This phenomenon takes place if the In-Ga-P melt is just supercooled. This instability of the liquid-solid interface is explained on the basis of the relaxation theory of non-equilibrium liquid-solid contact which has been created by the author in previous papers. n o~a a a~o , YTO xmnHaR #aaa In-Ga-P, c o a a a~~a a IIYT&M H a m u e m s U~O T~P M H~~C K I I M KOHTaKTOM C GaP HCTOYHMIEOM, CTaHOBATCII TIePeCblWeHHOfi B gefiCTBHTenbHOCTEI. OIIIICaHbI OC06eHHOCTA #OpMApOBaHHB In,Gal -,P/GaAs nJI&HOH. 6 b I J I O 06Hapy?~HO, YTO HaCbIWeH-Hati In-Ga-P XwiEKaa Qaaa pocTBopBeT GaAs no~noxwy B nposecce A X A~O T~~M H Y~C K O~O KoHTama, ecm paBHoBecHas Tsepnas paaa In,Gal -,P meeT napaMeTp pememn MeHbme, YeM y CaAe n o n n o x~~. B p e 3 y n b~a~e Taxoro Homama Hem6 InGaAsP cnol sb1nanae-r Ha IIO&lIOlfcKe. 3Ta OCO6eHHOCTb ElMeeT MeCTO Hame B TOM CnyYae, eCnM In-Ga-As PaCTBOp IIepecbIIqeH. TaKaa HeCTa6MJlbHOCTb rPaHHUbI paanena ?HIInIEOe-TBepAOe O~% B C H R~T C R Ha aBTOpOM B IIpenbIflYILWX pa6o~ax. ocHoBe Teopm penawaqmi HepaBHosecHol rpamubi paanena, KoTopaIi 6bina coanaaa