TEM is expensive, slow and lacks crucial information such as accurate composition and contamination distribution and concentration.
A smarter approach is to start with High Resolution SIMS depth profile to obtain:
- composition depth profile with ~1 nm depth resolution
- impurities depth profile with ~1 ppm detection (try with TEM!)
- interface contamination pile-up
A lot of ALD film quality is determined by the interface. Do not be stuck with standard TEM looking for answers.