Massachusetts Institute of Technology

L Rafael Reif

Vida Ilderem

Clifton G Fonstad

Prabha K Tedrow

Hae-Seung Harry Lee

K O Kenneth

Wayne R Burger

Thomas J Donahue

A vertical bipolar transistor is formed along with an IGFET transistor in a process in which the bipolar transistor collector, base and emitter structure is formed in the body of a semiconductor mesa-like structure while the IGFET transistor is formed in and along one of the sidewalls of the structure. Source and drain regions are formed in the structure by ion-implantation using a polysilicon gate electrode formed over a gate insulator on the sidewall as a self-aligning mask.

Merged bipolar and insulated gate transistors

The selective or blanket deposition of titanium silicide using a Very Low Pressure Chemical Vapor Deposition process is described. Silane and titanium tetrachloride are used as the silicon and titanium sources, respectively. A thin polysilicon layer is deposited prior to the silicide deposition to promote the nucleation of titanium silicide. It is shown that selective deposition is possible by controlling the polysilicon and the titanium silicide deposition times. The resulting titanium silicide films have resistivities in the range of 15-25 micro-ohms-cm.

Very low pressure chemical vapor deposition process for deposition of

A method and apparatus for forming epitaxial thin film layers on substrates having abrupt transitions between layers of different composition or layers of different or like composition with different degrees of doping included therein. Gaseous reactants containing the desired elements to be included in the first film layer are injected into a CVD reaction chamber containing a substrate. The substrate is heated to a temperature high enough to obtain an epitaxial deposit, but low enough so as not to cause decomposition of the reactants. Once the gaseous reactant flows reach steady-state, an electric discharge or plasma is created in the gases to initiate the decomposition reaction and obtain a deposit. In this way, no transient effects are present. Once the deposit has attained sufficient thickness, the electric discharge is turned off to abruptly terminate deposition. phase composition is then established for the next film to be deposited before again generating plasma in the gas reactants to deposit an epitaxial film of different composition or different degree of doping on top of the previous one.

Growth of epitaxial films by chemical vapor deposition

This invention relates to a process and apparatus for the Low Pressure Chemical Vapor Deposition (LPCVD) of polycrystalline refractory metal silicides, such as TiSi.sub.2, in a reactor. An oxidized Si wafer is loaded in the reactor. The reactor is pumped down to a pressure of about 10.sup.-7 Torr, or less. The Si substrate is heated to the predetermined deposition temperature of about 630.degree. C. while avoiding heating of the reactor walls. The reactor is then purged with an inert gas, such as nitrogen. Next, polysilicon is deposited on the wafer by introducing SiH.sub.4 into the reactor at a pressure in the order of 0.2 Torr. A layer of polycrystalline titanium silicide is then formed on the polysilicon layer by introducing reactants, such as TiCl.sub.4 and SiH.sub.4, into the reactor at depositon temperatures between about 650.degree. to 700.degree. C. and pressures of between about 50 to 460 m Torr.

Low pressure chemical vapor deposition of refractory metal silicides

A method and apparatus for forming epitaxial thin film layers on substrates having abrupt transitions between layers of different composition or layers of different or like composition with different degrees of doping included therein. Gaseous reactants containing the desired elements to be included in the first film layer are injected into a CVD reaction chamber containing a substrate. The substrate is heated to a temperature high enough to obtain an epitaxial deposit, but low enough so as not to cause decomposition of the reactants. Once the gaseous reactant flows reach steady-state, an electric discharge or plasma is created in the gases to initiate the decomposition reaction and obtain a deposit. In this way, no transient effects are present. Once the deposit has attained sufficient thickness, the electric discharge is turned off to abruptly terminate deposition. A new gas-phase composition is then established for the next film to be deposited before again generating plasma in the gas reactants to deposit an epitaxial film of different composition or different degree of doping on top of the previous one.

Growth of epitaxial films by plasma enchanced chemical vapor deposition

A method and apparatus for low temperature deposition of epitaxial films using low pressure chemical vapor deposition (CVD) with and without plasma enhancement. More specifically, the process enables CVD of epitaxial silicon at temperatures below 800.degree. C. by use of an in situ argon plasma sputter cleaning treatment of the silicon substrate prior to deposition.

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Newton, MA, United States of America

L Rafael Reif