A Samsung Electronics Co. 12-layer HBM3E memory chip.Photographer: SeongJoon Cho/BloombergSamsung Electronics Co. posted its biggest quarterly profit in more than three years, reflecting booming memory chip demand while AI development accelerates globally.South Korea’s largest company reported an operating profit of 12.1 trillion won ($8.5 billion) in the September quarter, compared with analysts’ projection for 9.70 trillion won, according to a preliminary earnings report released on Tuesday. R...