The invention concerns a method which consists in: (a) stabilization of the monocrystalline silicon substrate temperature at a first predetermined temperature T1 of 400 to 500° C.; (b) chemical vapour deposition (CVD) of germanium at said first predetermined temperature T1 until a base germanium layer is formed on the substrate, with a predetermined thickness less than the desired final thickness; (c) increasing the CVD temperature from said first predetermined temperature T1 up to a second predetermined temperature T2 of 750 to 850° C.; and (d) carrying on with CVD of germanium at said second predetermined temperature T2 until the desired final thickness for the monocrystalline germanium final layer is obtained. The invention is useful for making semiconductor devices.