Method for depositing layers of high quality semiconductor material

In a process for the plasma deposition of a layer of semiconductor material of the type wherein a process gas which includes a precursor of said semiconductor material is energized with electromagnetic energy so as to create a plasma therefrom, which plasma deposits a layer of said semiconductor material onto a substrate, said process being characterized by a group of deposition parameters comprising:

• process gas composition, process gas pressure, power density of said electromagnetic energy, and substrate temperature;
• wherein there is defined an amorphous/microcrystalline threshold for said deposition parameters such that there is a microcrystalline set of values for said deposition parameters wherein when said semiconductor material is deposited thereunder, it is microcrystalline, and an amorphous set of values for said deposition parameters wherein when said semiconductor material is deposited thereunder it is amorphous, and wherein said amorphous/microcrystalline threshold varies during the deposition of said semiconductor layer as a function of the thickness thereof;
• wherein the improvement comprises in combination:
• maintaining said deposition parameters at values which are within said amorphous set but which are near to the amorphous/microcrystalline threshold, during the entire time said layer of semiconductor material is being deposited by varying the value of at least one of said deposition parameters as a function of the thickness of the semiconductor material which has been deposited.