By Ju-min Park and Heekyong Yang

SEOUL, May 30 (Reuters) - Samsung Electronics' ( SSNLF )

new head of its chip division has called on staff to

work together to regain the company's status as a top

semiconductor company, adding he is committed to overcoming

challenges in an age of artificial intelligence.

The South Korean tech giant has fallen behind rivals SK

Hynix and Micron Technology ( MU ) in high bandwidth

memory (HBM) chips which are in high demand for use in AI

processors.

Citing a "chip crisis", it replaced its semiconductor chief

this month with Young Hyun Jun, who led Samsung's memory chip

business from 2014 to 2017 after working on the development of

DRAM and flash memory chips.

"This (AI era) poses a great challenge to us, but if we take

the right direction and respond, it can become an unprecedented

new opportunity," Jun, 63, said in a May 30 letter to staff

which was seen by Reuters.

Samsung's latest HBM chips have yet to pass Nvidia's ( NVDA )

tests for use in the U.S. firm's AI processors due to

heat and power consumption problems, three people briefed on the

issues have said. Samsung said in response that "claims of

failing due to heat and power consumption are not true," and

that testing was "proceeding smoothly and as planned."

Its weakness in HBM has been noticed by investors. While

shares in SK Hynix and Micron have both surged some 80% over the

past year, Samsung's shares are up just 6%.

Thursday's letter also noted that Samsung's semiconductor

division last year recorded its largest loss since the company

was founded, that its foundry business has not been able to

narrow the gap with a leading firm and that its system LSI

business was also struggling.

A Samsung union has also threatened to stage the company's

first walkout next week, calling for more transparency in pay as

well as additional annual leave.