iPhone 6S thicker
The so-called "iPhone 6s" could have a similar thickness to the iPhone 6 Plus. Robyn Beck/AFP/Getty Images

Apple’s quest for an ever thinner phone may be on hold. Schematics obtained by Engadget Japan show the anticipated “iPhone 6s” could be marginally thicker this time around.

Specifically, the design is expected to grow from a thickness of 6.9mm to 7.1mm -- the same girth as the iPhone 6 Plus. Aside from the size change, the overall look of the iPhone is expected to remain fairly similar.

The likely cause for the enlargement is the addition of a Force Touch display in the iPhone 6S, according to a research note issued by KGI Securities analyst Ming-Chi Kuo. The pressure-sensitive technology -- first introduced in the Apple Watch -- allows a trackpad or touchscreen to detect the difference between a tap or a hard press. If Force Touch is used in the iPhone 6s, it could enable new touch gestures, such as a contextual menu that pops up during a hard press.

The leak follows detailed iPhone 6S back cover and circuit board photos published last week by 9to5Mac. The smartphone is expected to pack a number of new features, such as a 12MP camera, A9 processor and 2GB of RAM.

Apple hasn’t officially announced a new iPhone just yet. But if it follows the trend of previous releases, it could unveil the iPhone 6s sometime in September, followed by sales a couple weeks later.