Kimberly G. Reid

Growth and surface chemistry of oxynitride gate dielectric using nitric oxide

Oxynitride films grown on preoxidized (100) silicon surfaces in a nitric oxide (NO) ambient at 950 °C have been investigated using x‐ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), atomic force microscopy (AFM), and cross‐sectional transmission electron microscopy (XTEM). Compared to N2O oxynitride, NO oxynitride exhibits very different surface chemistry, interface properties, and growth mechanisms. The etch back of NO and N2O oxynitride films allows control of sample thickness for the XPS measurements. NO oxynitride has the interfacial nitrogen (Nint) sharply peaked on the Si substrate side of the interface, while it is broad and on the dielectric side of the interface for the N2O oxynitride. The N(1s) XPS results reveal a clear distinction between N2O oxynitride and NO oxynitride. Near the Si/dielectric interface the NO oxynitride shows primarily Si≡N bonds, while the N2O films showed a N(1s) binding energy peak that is in‐between that of Si≡N bonds and Si2=N—O bonds. Furth...

Furnace grown gate oxynitride using nitric oxide (NO)

Gate oxynitride was grown in NO for the first time. This approach can provide a tight N accumulation near the Si/SiO/sub 2/ interface. Much lower thermal budget is required for an NO process than for an N/sub 2/O process to produce an oxynitride with useful properties. Submicron MOSFETs with NO oxynitride showed superior current drive characteristics and comparable hot carrier immunity to those with N/sub 2/O oxynitride. >

Gate oxynitride grown in nitric oxide (NO)

Gate oxynitride was grown in NO for the first time. This approach can provide a tight N accumulation near the Si/SiO/sub 2/ interface. Much lower thermal budget is required for an NO process than an N/sub 2/O process to produce an oxynitride with useful properties. Submicron MOSFETs with NO oxynitride showed superior current drive characteristics and comparable hot carrier immunity to those with N/sub 2/O oxynitride.<<ETX>>

Sub-quarter micron CMOS process for TiN-gate MOSFETs with TiO/sub 2/ gate dielectric formed by titanium oxidation

We report here for the first time the integration of sub-quarter micron CMOSFETs on bulk silicon using an oxidized metal gate dielectric. A polysilicon capped physical vapor deposited (PVD) titanium nitride (TiN) was used as the gate electrode. Well behaved MOSFET characteristics were obtained. In this paper, we present results on the physical and electrical characterization of titanium dioxide (TiO/sub 2/) produced by oxidizing a thin PVD Ti film.

Oxynitride gate dielectric grown in nitric oxide (NO): the effect of reoxidation on dielectric reliability of the active edge

Reoxidation of an oxynitride gate dielectric grown by NO anneal of thermal oxide has been studied. This process has demonstrated /spl sim/3-5X improvement of Q/sub BD/ of active edge intensive capacitors in comparison to thermal oxide, N/sub 2/O and NO oxynitride. This improvement is believed to be due to the reduction of local thinning of the gate dielectric at the field oxide edge which also reduces local build-up of positive charge near the gate electrode at the isolation edges.

Surface and Interface Roughness of Ultrathin Nitric Oxide Oxynitride Gate Dielectric

Surface and interface roughness of 40-A oxynitride films grown on preoxidized (100) silicon surfaces in a nitric oxide (NO) ambient at 800°C have been investigated using atomic force microscopy with power spectral density, and cross-sectional transmission electron microscopy measurements. The results showed that the NO oxynitride surface is smoother and has less interfacial roughness compared to the thermal oxide (without NO anneal). These results are important given the current technological interest in oxynitrides for ultrathin gate dielectric applications.

Uniformity of the N 2 O Furnace Oxynitride Process for the Formation of Thin Tunnel Dielectrics

We show that the properties of N 2 O oxynitride grown in a conventional horizontal furnace may vary down the tube. This could be a control issue when this material is used as the tunnel dielectric for electrically erasible programmable read-only memories (EEPROMs). We studied the effect of important process parameters on the electrical properties of N 2 O furnace oxynitrides It was found that oxynitride grown at a high flow rate does not suffer a variation down the tube and provides low electron trapping and robust Si/SiO 2 interface

Reoxidized nitric oxide (ReoxNO) process and its effect on the dielectric reliability of the LOCOS edge

Reoxidation of an oxynitride gate dielectric grown by NO anneal of thermal oxide has been studied for the first time. This process results in a striking enhancement of both gate and substrate injection Q/sub BD/ by /spl sim/3-5X for active edge intensive capacitors in comparison to thermal oxide, N/sub 2/O and NO oxynitride. This improvement is attributed to reduction of mechanical stress at the active edge which leads to less local thinning of gate oxide at the field oxide edge and reduction of the local build-up of positive charge near the gate electrode at the isolation edges. Drive current of n- and p-MOSFETs with ReoxNO oxynitride is also compared to other dielectrics.

High Temperature Thermal Processing for Ulsi Applications

The diversity of semiconductor manufacturing as well as the decreasing thermal budget for ULSI devices has driven semiconductor equipment manufacturers to develop and improve thermal processing solutions. Recent advances include new temperature measurement systems for rapid thermal processors (RTP), the development of the small batch fast ramp furnace (SBFR), as well as improved capability and load size in the conventional vertical batch furnace (BF). This paper will review the RTP, SBFR, and batch furnace for typical atmospheric front end of the line applications. Throughput and cycle time will be modeled for each type of system. Sematechs cost of ownership model will be employed to evaluate the relative importance of throughput, mean time between failure, and equipment cost. And finally an overview discussion of the issues associated with temperature measurement and system configurations of the RTP will be given.

Tantalum Pentoxide Gate Dielectrics Formed by Tantalum Oxidation

Tantalum pentoxide (Ta 2 O 5 ) films were formed by oxidizing thin tantalum (Ta) films on bare and NO-nitrided silicon substrates. The 43-400 A thick Ta films were deposited using physical vapor deposition (PVD) and oxidized using O 2 for 2-60 min at 550-800 C in a furnace or single wafer tool. Uniform and stoichiometric Ta 2 O 5 films were successfully produced as determined from XRD, AES depth profiling, XTEM, and ellipsometric analysis. The nitridation pretreatment was found to minimize the interfacial Ta-Si reactions which occur during the oxidation. Well-behaved CV and IV curves were obtained from mercury probe measurements. No CV hysteresis was observed. An equivalent oxide thickness of 38 A and a leakage current of 7×10 −9 A/cm 2 at +1V were obtained for a 120 A thick Ta 2 O 5 film on a 15 A interfacial SiO 2 layer.