A polymerization process comprising (A) polymerizing ethylene and optionally one or more alpha-olefins in the presence of a catalyst to form a semi-crystalline ethylene-based polymer in at least one reactor; the catalyst comprising an organometallic catalyst thereby forming an ethylene-based polymer composition in the at least one reactor, wherein the catalyst is a metal complex of a polyvalent aryloxyether corresponding to the formula: [Formula I] where M3 is Ti, Hf or Zr, preferably Zr; Ar4 is independently in each occurrence a substituted C9-20 aryl group, wherein the substituents, independently in each occurrence, are selected from the group consisting of alkyl; cycloalkyl; and aryl groups; and halo-, trihydrocarbylsilyl- and halohydrocarbyl- substituted derivatives thereof, with the proviso that at least one substituent lacks co-planarity with the aryl group to which it is attached; T4 is independently in each occurrence a C2-20 alkylene, cycloalkylene or cycloalkenylene group, or an inertly substituted derivative thereof; R21 is independently in each occurrence hydrogen, halo, hydrocarbyl, trihydrocarbylsilyl, trihydrocarbylsilylhydrocarbyl, alkoxy or di(hydrocarbyl)amino group of up to 50 atoms not counting hydrogen; R3 is independently in each occurrence hydrogen, halo, hydrocarbyl, trihydrocarbylsilyl, trihydrocarbylsilylhydrocarbyl, alkoxy or amino of up to 50 atoms not counting hydrogen, or two R3 groups on the same arylene ring together or an R3 and an R21 group on the same or different arylene ring together form a divalent ligand group attached to the arylene group in two positions or join two different arylene rings together; and RD is independently in each occurrence halo or a hydrocarbyl or trihydrocarbylsilyl group of up to 20 atoms not counting hydrogen, or 2 RD groups together are a hydrocarbylene, hydrocarbadiyl, diene, or poly(hydrocarbyl)silylene group; wherein step (A) is conducted in the presence of from 5 to 20 mmol/m3 triethylaluminum; and wherein step (A) is conducted in the presence of one or both of the following conditions: (i) from greater than 0:1 to 65:1 molar ratio of triethylaluminum to the catalyst; and (ii) from 0.1:0 to 5:1 molar ratio of triethylauminum to modified methylalumoxane is provided.