| 摘要 |
A known method of manufacturing, for example, lasers comprises the deposition, on a substrate (1), of semiconductor layers from a gas (3) which includes at least two reactive components, such as TMG and arsine to form GaAs. The substrates (1) are arranged, within a reactor (10), on a supporting plate (2), heated and, preferably, rotated about their own center and the center of the supporting plate (2). Arsine (4) is supplied centrally above the supporting plate (2), and TMG (5) is supplied directly around said arsine, but separated therefrom, said TMG terminating at a larger distance from the supporting plate (2). These gases (4, 5) then flow sideways across the supporting plate (2) covered with substrates (1) and are discharged at the side thereof. Such a method results in a good homogeneity of the properties of the deposited semiconductor layer, which is crucial to many semiconductor devices. However, the spread, particularly, in the thickness but also in the composition, both within a substrate (1) and between two or more substrates (1) within a single deposition, as well as between different depositions, leaves to be desired. In accordance with the invention, the TMG gas flow (5) is built up of n, n being greater than or equal to two, individual gas sub-flows (5A), each supplying 1/n th part of the second gas flow (5) and being supplied symmetrically with respect to the center of the supporting plate (2). Surprisingly, it has been found that this results in a substantial improvement of the above-mentioned homogeneities, in particular when the deposited semiconductor layer is very thin. Preferably, the TMG gas flow (5) is built up of an even number, preferably 4, gas sub-flows (5A). For this purpose, a device in accordance with the invention is equipped with a corresponding number of supply tubes (6). Use can further advantageously be made of a mixing chamber (13) for the gas sub-flows (5A) from which, for example at least twice as many, further gas sub-flows (5B) flow towards the supporting plate (2).
|
