nitrogen at the interface apparently promoted wetting of the molten silicon on the sio 2 cap by lowering the contact angle as shown in fig3 the present invention represents a better technique for introducing an appropriate amount of nitrogen to the poly si cvd sio 2 cap interface in a uniform controlled fashion resulting in improved soi films after zmr the capped soi structure of fig2 with no nitride cladding is annealed before zmr at a temperature substantially below the melting point of silicon in an atmosphere rich in reactive nitrogen a wide range of process parameters are effective however a 100 nh 3 atmosphere at 1100 u00b0 appears to work best at this temperature the gas decomposes sufficiently at the sio 2 surface allowing nitrogen atoms to diffuse through the sio 2 cap the cap silicon interface appears to have an affinity for nitrogen atoms after the high temperature anneal a concentration of nitrogen exists at the interface with a concomitant improvement in wetting properties after annealing the treated wafer is inserted in the heating apparatus of fig1 for zmr of the silicon because of the lowered contact angle at the si sio 2 cap boundary beading or stripping of the molten silicon is suppressed and stress on the cap is thereby sufficiently diminished to leave the cap intact if too much n is present at the si sio 2 cap boundary although wetting is excellent zmr.