Formation of a layer on a semiconductor substrate

A method for growing an epitaxial III-V layer on a substrate, the method comprising:

• in a pre-clean chamber, and while the substrate is at a first temperature, T1, exposing the substrate to a plasma, products of plasma decomposition, or both the plasma and the products of plasma decomposition so as to remove native oxide from the substrate and form a passivation layer on the substrate, wherein T1 is greater than room temperature, and wherein the passivation layer comprises a hydrogen terminated (Si—H) surface;
• in an oxygen-free environment, (a) transferring the substrate from the pre-clean chamber to a deposition chamber, and (b) cooling the substrate from T1 to a second temperature, T2;
• and
• in the deposition chamber, (a) heating the substrate from T2 to a third temperature, T3, so as to remove the passivation layer on the substrate, wherein removing the passivation layer comprises transforming the hydrogen terminated (Si—H) surface by flowing a group V precursor into the deposition chamber, and wherein 50° C.<T3<700° C., and (b) growing the epitaxial III-V layer on the substrate, wherein growing the epitaxial III-V layer on the substrate comprises sequentially performing the following steps in the deposition chamber:
• (i) cooling the substrate from T3 to a fourth temperature, T4;
• (ii) when the substrate is at T4, starting a flow of a group III precursor so as to deposit a III-V nucleation layer on the substrate;
• (iii) stopping the flow of the group III precursor;
• (iv) heating the substrate to a fifth temperature, T5;
• (v) when the substrate is at T5, re-starting the flow of the group III precursor so as to deposit a bulk III-V layer over the III-V nucleation layer;
• (vi) stopping the flow of the group III precursor;
• and
• (vii) cooling the substrate from T5 to a sixth temperature, T6, wherein the flow of the group III precursor is stopped in step (iii), while the substrate temperature is less than T4.