Valuation of an ETF comes down to the valuation of the individual components. Behind the underlying theme are the underlying companies.

These are the top 10 holdings which account for 70% of the Semi ETF:

ASML HOLDINGS NV

NVIDIA CORP

TSMC

INTEL CORP

BROADCOM INC

TEXAS INSTRUMENT

QUALCOMM INC

ADV MICRO DEVICE

APPLIED MATERIAL

ANALOG DEVICES

These companies are all fairly mature businesses, albeit continuing to grow. I'd guess that 15-20%pa CAGR is achievable. That's good, but you aren't going to shoot the lights out with this ETF.