An apparatus in a chemical vapor deposition (CVD) system monitors the actual wafer/substrate temperature during the deposition process. The apparatus makes possible the production of high quality aluminum oxide films with real-time wafer/substrate control. An infrared (IR) temperature monitoring device is used to control the actual wafer temperature to the process temperature setpoint. This eliminates all atmospheric temperature probing. The need for test runs and monitor wafers as well as the resources required to perform the operations is eliminated and operating cost are reduced. High quality, uniform films of aluminum oxide can be deposited on a silicon substrates with no need for additional photolithographic steps to simulate conformality that are present in a sputtered (PVD) type application. The result is a reduction in required process steps with subsequent anticipated savings in equipment, cycle time, chemicals, reduce handling, and increased yield of devices on the substrate. The apparatus incorporates a heated source material, heated delivery lines, heated inert gas purge lines, a pressure differential mass flow controller, a control system with related valving, and a vacuum process chamber with walls that are temperature controlled as a complete source delivery system to accurately and repeatably provide source vapor for LPCVD deposition of aluminum oxide onto silicon substrates.