Samsung is the single largest producer of smartphones of in the world as they have recently overtaken Apple. Their flagship Galaxy S3 has outsold even the iPhone and more of the same is expected from the soon to be released galaxy s4. Apparently they have inherited some of Apple's old supply issues as they now are searching for alternative sources for processor components. The Inside sources who provided the info said that the main cause of the issues was the massively popular galaxy line of smartphones.
Samsung is having difficulty finding sources for critical NAND flash storage, eMMC devices and worst of all Mobile DRAM. Samsung is reaching out to Toshiba to supply the NAND flash and the eMMC devices. Elpida Memory was supposedly chosen for the actual DRAM, a potentially risky choice as they filed for bankruptcy just last year. They supposedly will be the suppliers for the 5s as well, hopefully they will be able to produce enough for both companies.
Strangely it appears that most of the Japanese parts Samsung is purchasing will go into processors that they build for other companies, while they keep their in house produced components for their own smartphones and tablets. Hopefully this will not result in sub par performance from the companies who trust Samsung as a supplier but there can be no guarantee.
It would be nice if companies could somehow produce all of their own components. Unfortunately the process of building a phone is insanely complex. The Samsungs and HTCs of the world are forced to rely upon smaller component makers and hope they come through. Every once in a while they don't and companies like Elpida have to be called on to fill the gaps. The Galaxy S4 being available as soon as possible will be critical for the future and current success of Samsung. It would be unfortunate to see the supply issue that plague phones like the HTC One delaying the release of the octo-core beast.