Master's Research Thesis vs. PhD Thesis
German perspective:
Master theses are short (duration-wise), PhD theses are long. How short and how long depends on details, but the relative difference is there regardless.
Master theses consist of one problem, while in STEM, PhD theses are often a collection of works which are not necessarily very closely related.
Both should contain original results. A 6-12 month master thesis which does not contain any original results has significant shortcomings.
From a supervisor's perspective: A master thesis which leads to one paper in a reputable journal is a good (top 1/3 or so) master thesis. A PhD thesis which only gives rise to one paper is a below average (lower 1/3) PhD thesis.