Lead Researcher: Dr. Robert Nemanich Graduate Students: Xin Liu, Chiyu Zhu, Yang Sun, Manpuneet Kaur, Fu Tang, and others... Teacher Researchers: Amber Strunk and Kelli Gamez Warble
Research: Dr. Nemanich's lab focuses on material surfaces on the nanometer scale. There are many ongoing projects in lab at this time studying the properties of germanium, vanadium, silicon dioxide, hafnium dioxide, and cleaning properties of various plasmas. The lab utilizes many different types of equipment to prepare samples and to collect data.
Our Research Goal: We are trying to form "quantum dots" of vanadium on a silicon wafer. To do this we will have to follow these general steps:
Step One: Cut, clean, and mount a silicon wafer for insertion into a vacuum chamber. DON'T CRACK THE SAMPLE!
Step Two: Insert mounted silicon wafer into the vacuum system via the load lock
Step Three: Transfer the sample (inside the vacuum system) to the oxygen plasma chamber via the transfer line. DON'T DROP THE SAMPLE. The oxygen plasma rids the sample of further impurities. In particular oxygen plasma is good for removing hydrocarbons from the sample.
The transfer line runs the length of the vacuum system and connects all the chambers it is approximately 46 feet in length.
Oxygen plasma chamber
Step Four: After cleaning in the oxygen plasma the sample will be transferred to the molecular beam epitaxy (MBE) chamber. Epitaxy refers to depositing monocrystallin film on a monocrystalline substrate. In our case we will use it to deposit a vanadium layer of 1-2 nm onto a silicon wafer. The material is heated until it sublimates and than the gaseous element condenses onto the wafer. The MBE is very slow so depending on the thickness of the layer you need it can be time consuming.
Molecular Beam Epitaxy Chamber
Step Five: Transfer the sample to the Xray photoemission spectroscopy (XPS) chamber to get a base line data for the sample. XPS is a way of measuring the chemical make up of a sample by exciting the sample with xrays and than measuring the photoemissions seen from the sample. We can than determine the composition of the sample by then comparing the measured photoemissions to known values of various materials.
Xray photoemission spectroscopy
Step Six: Transfer the sample to the heating chamber and heat at 300 degrees Celsius. When finished return to the XPS chamber any changes to the percentage of vanadium vs. underlying silicon on the surface of the chip.
Step Seven: Repeat the heating process increasing the temperature by 200 degrees each time until XPS indicates a greater percentage of silicon "showing", implying that the vanadium has coalesced into droplets on the surface of the silicon Step Eight: Remove the sample from the vacuum system to view it using the atomic force microscope(AFM) to observe the topography of the vanadium droplets.
Vanadium Nanodots
Lead Researcher: Dr. Robert Nemanich
Graduate Students: Xin Liu, Chiyu Zhu, Yang Sun, Manpuneet Kaur, Fu Tang, and others...
Teacher Researchers: Amber Strunk and Kelli Gamez Warble
Research: Dr. Nemanich's lab focuses on material surfaces on the nanometer scale. There are many ongoing projects in lab at this time studying the properties of germanium, vanadium, silicon dioxide, hafnium dioxide, and cleaning properties of various plasmas. The lab utilizes many different types of equipment to prepare samples and to collect data.
Our Research Goal: We are trying to form "quantum dots" of vanadium on a silicon wafer. To do this we will have to follow these general steps:
Step One: Cut, clean, and mount a silicon wafer for insertion into a vacuum chamber. DON'T CRACK THE SAMPLE!
Step Two: Insert mounted silicon wafer into the vacuum system via the load lock
Step Three: Transfer the sample (inside the vacuum system) to the oxygen plasma chamber via the transfer line. DON'T DROP THE SAMPLE. The oxygen plasma rids the sample of further impurities. In particular oxygen plasma is good for removing hydrocarbons from the sample.
Step Four: After cleaning in the oxygen plasma the sample will be transferred to the molecular beam epitaxy (MBE) chamber. Epitaxy refers to depositing monocrystallin film on a monocrystalline substrate. In our case we will use it to deposit a vanadium layer of 1-2 nm onto a silicon wafer. The material is heated until it sublimates and than the gaseous element condenses onto the wafer. The MBE is very slow so depending on the thickness of the layer you need it can be time consuming.
Step Five: Transfer the sample to the Xray photoemission spectroscopy (XPS) chamber to get a base line data for the sample. XPS is a way of measuring the chemical make up of a sample by exciting the sample with xrays and than measuring the photoemissions seen from the sample. We can than determine the composition of the sample by then comparing the measured photoemissions to known values of various materials.
Step Six: Transfer the sample to the heating chamber and heat at 300 degrees Celsius. When finished return to the XPS chamber any changes to the percentage of vanadium vs. underlying silicon on the surface of the chip.
Step Seven: Repeat the heating process increasing the temperature by 200 degrees each time until XPS indicates a greater percentage of silicon "showing", implying that the vanadium has coalesced into droplets on the surface of the silicon
Step Eight: Remove the sample from the vacuum system to view it using the atomic force microscope(AFM) to observe the topography of the vanadium droplets.